Cache issue: Wrong files used when gallery is invoked by K9 Mail

Checklist

[X] I can reproduce the bug with the latest version given here.
[X] I made sure that there are no existing issues - open or closed - to which I could contribute my information.
[X] I made sure that there are no existing discussions - open or closed - to which I could contribute my information.
[X] I have read the FAQs inside the app (Menu -> About -> FAQs) and my problem isn't listed.
[X] I have taken the time to fill in all the required details. I understand that the bug report will be dismissed otherwise.
[X] This issue contains only one bug.
[X] I have read and understood the contribution guidelines.

Affected app version

1.1.3

Affected Android/Custom ROM version

Android 11

Affected device model

Nokia 7.2

How did you install the app?

GitHub releases

Steps to reproduce the bug

Open Email with JPEG attachement within K9 Mail aka Thunderbird Mobile in future.
K9 shows correct thumbnail of appended jpeg.
Click on thumbnail
Android asks for "open with", select Fossify Gallery, once or always
Wrong picture shown

Expected behavior

Appended picture should be opened shown in Gallery

Actual behavior

This issue appears more or less reproducable FIRST after a while, after having received a lot of emails of this type. When happening first, after that point not always, but more and more often. These emails are sent from a video doorbell, attachement has always the same file name, e.g. PIC01.JPG. When Gallery is invoked from K9 Mail, file name shown in Gallery is somewhat like a large hex string, like a GUID. If a "wrong" file is shown by Gallery, this file is ALLWAYS a picture previously received from the doorbell. That's why my assumption was caching mechanism issue. Deleted Gallery's cache, stopped and (re)started Gallery: Issue GONE. For a while, issue reappears after an unknown for me amount of this specific emails received.

NO IDEA who handles, triggers the file name / caching mechanism, maybe K9 is the culprit :)

If say "save attachement", original file name is used, and opening it from Fossify File Manager to Gallery works fine.

IMHO a hint that's a Gallery issue is the following:

resetted the open with settings to "ask"
click on attachement
a) open with Gallery: WRONG picture
b) repeat 2. and open with e.g. Orion (PDF) Viewer: CORRECT picture is shown, ALTHOUGH long hex Guid-style file name is the same.

Screenshots/Screen recordings

No response

Additional information

No response

FossifyOrg / Gallery