Illegal character confusion/bad ux

[l300lvl]

Not necessarily a bug but this one had me stumped several times. To reproduce this:

Try to copy any file with other files as a group transfer with a quote symbol in the filename of any of the files and the transfer dialog simply pauses and never completes, with no visible warning or error. It just seems to hang eternally.

The way I did detect what is happening is by copying a single file with the bad character, when transferring only one file an illegal character notice is indeed given. When transferring multiple files some good/some with the illegal char, no notice ever came up.

To be sure, I renamed the file after getting the notice, and it indeed copied.

What really really boggles my mind is: if I compress a file containing the illegal character and transfer the zip and extract it under the phone, the character exists just fine? Is it really so illegal?