Windows 10: aspell called from within makefile does not remember dictionary words

Hi,

I have always run aspell from within my makefiles and it worked under
Windows 7 with cygwin.

Now, I am trying the same under Windows 10 with cygwin and I find that
aspell does not remember the words I manually add to the dictionary.

Makefile:
all:
	aspell --encoding=utf-8 --lang=en_gb --mode=tex -c test.tex;

text.tex:
Heer I wraight everising frong!


If I just run "make" and add all the incorrect words, the next time I
run "make", the words are again recognised as wrong and there are no
changes in C:\Users\Linus\AppData\Local\VirtualStore\Program Files
(x86)\Aspell\en.pws.

If I run "aspell --encoding=utf-8 --lang=en_gb --mode=tex -c test.tex"
directly from the command line, however, it works.

Any ideas how to fix this?

Thanks,
Linus