Truncating of file name

[erydit]

Just met a strange issue.
I download a file from my mail box using Firefox, and try to save it in a mounted encfs directory. The file named "Рязанов_Геосферные исследования_с_правками_07072021 (1).doc"
After saving the file name becomes "Рязанов_Геосферные исследования_с_правками.doc" - without the "_07072021 (1)" part.

When i download the file in another directory first (say into Desktop) and then move it into encfs dir, the file name stay unchanged - "Рязанов_Геосферные исследования_с_правками_07072021 (1).doc".

If i manually rename the file with truncated filename to its original full name, it stays with it. So it is not a name length issue.

Maybe I just dont know about some mechanics or settings?

[Keisial]

Can you still reproduce this?

[erydit]

Can you still reproduce this?

Sorry, it was quite a long time ago. I have switched to gocryptfs since then.