Update multiple photos with IPTC does not work

[digital]

Hello

I set IPTC tags for my photos (.tif). For this I select several files and press CTRL-I, then fill in the fields. It works, but only the first time. If fields like Caption, Headline or Create Date are already filled in and I want to change them (with several selected photos), the change will not be applied anymore! The file gets a few bits bigger, but the fields are not saved. I have to edit/update each file individually, which is very tedious!
I have also already activated the option "Don't load field Values", without success.

What am I doing wrong?
Have this version:
XnView MP Windows
Version 0.96.5 64bits (Aug 17 2020)
The previous version did not work either.

Thanks

[xnview]

what do you have in IPTC dialog>settings?

[digital]

Never seen this before

All options are activated, but cannot be changed. Not even if I change the mode.

xnview.png

[xnview]

select more than 1 picture file, and uncheck 'replace only if original value is empty'

[digital]

Thanks a lot, now it works!