[Thunderbird portable] Permissions issue

Hello all, so i have upgrade Thunderbird yesterday from 45.4.0 to the last one 45.8.0 and all of sudden i have issues to open mail attachment in firefox (or other software), expecially PDF documents.

The error i get is "access denied".

Seems there is a bug in the subfolder (tipically created as xxxxxxx.tmp) that the program create everytime at startup (and where it store attachments) along with some dll into my temporary system folder (in my case c:\temp), infact if i set manually the permission of the whole temp folder again the PDF file is perfectly readable, but the setting is lost everytime i close Thunderbird and reopen it, and so i have to manually re-set permissions again. Is a true hell.

This bug affect all version above the 45.4.0, every version prior of this haven't the issue, just tested.

Atm i have downgrade to 45.4.0 and infact it wirk perfectly, so can you guys please fix this issue?

I run windows 7 X64 sp1. Thanks you.