Slime startup sometimes: Undefined function SWANK::SYMBOL-INDENTATION

I frequently see this (see debugger backtrace below) when starting SLIME. Not all the time. I suspect it's a timing issue.  Anyone see this?  Anyone looked into fixing?

Thanks,

--Mark

Undefined function SWANK::SYMBOL-INDENTATION called with arguments (:BREAK-OPTIONS-STRING) .
   [Condition of type CCL::UNDEFINED-FUNCTION-CALL]

Restarts:
 0: [CONTINUE] Retry applying SWANK::SYMBOL-INDENTATION to (:BREAK-OPTIONS-STRING).
 1: [USE-VALUE] Apply specified function to (:BREAK-OPTIONS-STRING) this time.
 2: [STORE-VALUE] Specify a function to use as the definition of SWANK::SYMBOL-INDENTATION.
 3: [ABORT-BREAK] Reset this thread
 4: [ABORT] Kill this thread

Backtrace:
  0: ((:INTERNAL SWANK::CONSIDER SWANK::UPDATE-INDENTATION/DELTA-FOR-EMACS) :BREAK-OPTIONS-STRING)
  1: (#<Anonymous Function #x302000BD1E4F> :BREAK-OPTIONS-STRING)
  2: (CCL::APPLY-TO-HTAB-SYMS #<COMPILED-LEXICAL-CLOSURE #x2389553F> #(:NFRAMES #<Unbound> :CODE 0 :PAUSE-PERIOD 0 ...))
  3: (CCL::ITERATE-OVER-PRESENT-SYMBOLS #<Package "KEYWORD"> #<COMPILED-LEXICAL-CLOSURE #x2389553F>)
  4: (CCL::ITERATE-OVER-ALL-SYMBOLS #<COMPILED-LEXICAL-CLOSURE #x2389553F>)
  5: (SWANK::UPDATE-INDENTATION/DELTA-FOR-EMACS #<HASH-TABLE :TEST EQ size 228/305 #x302000AC574D> (#<Package "X86-DARWIN64"> #<Package "X8664"> #<Package "KEYWORD"> #<Package "CCL"> ..) #<Package "COMMON-..
  6: (SWANK::PERFORM-INDENTATION-UPDATE #<MULTITHREADED-CONNECTION #x302000AC56AD> (#<Package "X86-DARWIN64"> #<Package "X8664"> #<Package "KEYWORD"> #<Package "CCL"> #<Package "COMMON-LISP"> ..) #<Package..
  7: ((:INTERNAL SWANK::INDENTATION-CACHE-LOOP))
  8: (SWANK/BACKEND:CALL-WITH-DEBUGGER-HOOK #<Compiled-function SWANK:SWANK-DEBUGGER-HOOK #x302000A414FF> #<COMPILED-LEXICAL-CLOSURE (:INTERNAL SWANK::INDENTATION-CACHE-LOOP) #x302000ACFD1F>)
  9: (SWANK::INDENTATION-CACHE-LOOP #<MULTITHREADED-CONNECTION #x302000AC56AD>)
 10: (CCL::RUN-PROCESS-INITIAL-FORM #<PROCESS swank-indentation-cache-thread(6) [Active] #x302000AC982D> (#<COMPILED-LEXICAL-CLOSURE (:INTERNAL CCL::%PROCESS-RUN-FUNCTION) #x302000AC95BF>))
 11: ((:INTERNAL (CCL::%PROCESS-PRESET-INTERNAL (PROCESS))) #<PROCESS swank-indentation-cache-thread(6) [Active] #x302000AC982D> (#<COMPILED-LEXICAL-CLOSURE (:INTERNAL ..)))
 12: ((:INTERNAL CCL::THREAD-MAKE-STARTUP-FUNCTION))