Hello Makreel, those temp files are used by Bitdefender when new malware definition signatures are being updated. Those are False Positives.
It's always advisable when Immunet is used as a companion AV to exclude the entire Program Files folder of the other AV in Immunet's Exclusion List if it's not already there by default. Do the same for Immunet too, exclude Immunet's Program Files folder with Bitdefender. That can go a long way to help avoid possible conflicts and that should fix the Temp files being mistakenly flagged.
In fact, delete that Windows Temp file exclusion once you've made an exclusion for Bitdefender's entire Program Files folder to see if the same behavior occurs. I don't think it should but let us know if it does because if you create a generic exclusion for the Windows Temp file directory that can leave your system more vulnerable to exploits. It's "definitely not" recommended!
Best wishes, Ritchie...