Many users have reported this issue to us. They do not understand why it happens. The bug is still there, and F-Droid maintainers don't care: https://gitlab.com/fdroid/fdroidclient/-/work_items/2850
No problem on searching, finding and installing on F-Droid.
Organic Maps is marked with attached security advice, so if users configure strict matching they probably can't proceed...
@manankanchu it works for you, because you have changed that setting.
BTW, F-Droid deliberately misinforms users by labeling Organic Maps as such:
1. Our binary files are free assets and can be used by anyone. They are under a FOSS license that requires proper attribution.
2. The fact that the app downloads its maps from the app's CDN does not make the app "bad".
But that's another story/narrative pushed towards OM by some of the F-Droid guys.
Let's focus now on the installation issue.
" ... it works for you, because you have changed that setting."
Nope .... vanilla install