Leap 15.6->16.0 upgrade, filesystem package fails, xmv: Illegal instruction (core dumped)

Hello,
I am trying to upgrade a server from Leap 15.6 to Leap 16.0 using
"zypper dup"
Getting this error during install of "filesystem":

Make a copy of `/bin'.
Merge the copy with `/usr/bin'.
Clean up duplicates in `/usr/bin'.
Make a copy of `/sbin'.
Merge the copy with `/usr/sbin'.
Clean up duplicates in `/usr/sbin'.
Make a copy of `/lib'.
Merge the copy with `/usr/lib'.
Clean up duplicates in `/usr/lib'.
Make a copy of `/lib64'.
Merge the copy with `/usr/lib64'.
Clean up duplicates in `/usr/lib64'.
Switch to new `/usr/bin'.
/usr/libexec/convertfs: line 95: 13448 Illegal instruction     (core
dumped) /usr/libexec/xmv "$ROOT/usr/${dir}.usrmerge" "$ROOT/usr/$dir"
UsrMerge conversion failed, cleaning up !!! ATTENTION: Do NOT proceed
if you see this message during !!! distribution upgrade. Chances are
high that your system might !!! break beyond repair if you do.
error: lua script failed: [string
"%prein(filesystem-84.87-160000.2.2.x86_64)"]:22: exit error:
filesystem-84.87-160000.2.2.x86_64: install failed error:
filesystem-15.0-11.8.1.x86_64: erase skipped

obviously the statically linked "/usr/libexec/xmv" fails with an illegal
instruction.

some details:

dmesg: 
[Fr Jul 10 12:25:38 2026] traps: xmv[13448] trap invalid opcode
ip:403266 sp:7ffc3d848320 error:0 in xmv[401000+7c000]

(132)(0)theta:~ # /usr/libexec/xmv
Illegal instruction (core dumped)
(132)(0)theta:~ # rpm -qf /usr/libexec/xmv
compat-usrmerge-tools-84.87-160000.2.2.x86_64
(0)(0)theta:~ # rpm -V  "
(0)(0)theta:~ # file /usr/libexec/xmv
/usr/libexec/xmv: ELF 64-bit LSB executable, x86-64, version 1
(GNU/Linux), statically linked, for GNU/Linux 4.3.0,
BuildID[sha1]=19da4dfbda12e06105e4e146d727e156e2f7e1fd, stripped
(0)(0)theta:~ # stat /usr/libexec/xmv File: /usr/libexec/xmv Size:
710392          Blocks: 1392       IO Block: 4096   regular file
Device: 24h/36d Inode: 25281519    Links: 1 Access: (0755/-rwxr-xr-x)
Uid: (    0/    root)   Gid: (    0/    root) Access: 2026-07-10
10:55:05.124812654 +0200 Modify: 2021-10-07 13:57:22.000000000 +0200
Change: 2026-07-10 10:53:36.623182529 +0200
 Birth: 2026-07-10 10:53:36.607182234 +0200

(0)(0)theta:~ # coredumpctl info /usr/libexec/xmv
           PID: 31918 (xmv)
           UID: 0 (root)
           GID: 0 (root)
        Signal: 4 (ILL)
     Timestamp: Fri 2026-07-10 12:49:31 CEST (1min 32s ago)
  Command Line: /usr/libexec/xmv
    Executable: /usr/libexec/xmv
 Control Group: /user.slice/user-1000.slice/session-14.scope
          Unit: session-14.scope
         Slice: user-1000.slice
       Session: 14
     Owner UID: 1000 (pane)
       Boot ID: 23b1591d473a4d93a5779ebe10e9a4ce
    Machine ID: 122a20392f7df445044a23765a50986d
      Hostname: theta
       Storage:
/var/lib/systemd/coredump/core.xmv.0.23b1591d473a4d93a5779ebe10e9a4ce.31918.1783680571000000.zst
(present) Size on Disk: 9.8K Message: Process 31918 (xmv) of user 0
dumped core. 
                Stack trace of thread 31918:
                #0  0x0000000000403266 n/a (/usr/libexec/xmv + 0x3266)
                #1  0x0000000000404131 n/a (/usr/libexec/xmv + 0x4131)
                #2  0x0000000000401ac5 n/a (/usr/libexec/xmv + 0x1ac5)
                ELF object binary architecture: AMD x86-64

(0)(0)theta:~ # lscpu
Architecture:                x86_64
  CPU op-mode(s):            32-bit, 64-bit
  Address sizes:             36 bits physical, 48 bits virtual
  Byte Order:                Little Endian
CPU(s):                      2
  On-line CPU(s) list:       0,1
Vendor ID:                   GenuineIntel
  Model name:                Intel(R) Pentium(R) D CPU 3.00GHz
    CPU family:              15
    Model:                   6
    Thread(s) per core:      1
    Core(s) per socket:      2
    Socket(s):               1
    Stepping:                5
    CPU(s) scaling MHz:      80%
    CPU max MHz:             3000.0000
    CPU min MHz:             2400.0000
    BogoMIPS:                5999.66
    Flags:                   fpu vme de pse tsc msr pae mce cx8 apic
sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss
ht tm pbe syscall nx lm constant_tsc pebs bts nopl cpuid pni dtes64
monitor ds_cpl est cid cx16 xtpr pdcm lahf_lm pti Caches (sum of all):
L1d:                       32 KiB (2 instances) L2:
   4 MiB (2 instances) NUMA: NUMA node(s):              1
  NUMA node0 CPU(s):         0,1
Vulnerabilities:             
  Gather data sampling:      Not affected
  Indirect target selection: Not affected
  Itlb multihit:             KVM: Mitigation: VMX unsupported
  L1tf:                      Mitigation; PTE Inversion
  Mds:                       Vulnerable: Clear CPU buffers attempted,
no microcode; SMT disabled Meltdown:                  Mitigation; PTI
  Mmio stale data:           Unknown: No mitigations
  Reg file data sampling:    Not affected
  Retbleed:                  Not affected
  Spec rstack overflow:      Not affected
  Spec store bypass:         Vulnerable
  Spectre v1:                Mitigation; usercopy/swapgs barriers and
__user pointer sanitization Spectre v2:                Mitigation;
Retpolines; STIBP disabled; RSB filling; PBRSB-eIBRS Not affected; BHI
Not affected Srbds:                     Not affected Tsa:
        Not affected Tsx async abort:           Not affected
  Vmscape:                   Not affected
(0)(0)theta:~ # grep -m1 '^flags' /proc/cpuinfo
flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge
mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe
syscall nx lm constant_tsc pebs bts nopl cpuid pni dtes64 monitor
ds_cpl est cid cx16 xtpr pdcm lahf_lm pti



How to recover/continue the upgrade?
My idea would be maybe re-installing Leap 15.6's
"compat-usrmerge-tools", add a lock and retry zypper dup?

No idea how inconsistent the state of the system got by the failed
zypper dup.

Thanks for any hints.
Regards,

Paul