The detailed explanation is in this post: FAIRPHONE 3 and 3+ A13 - Fingerprint sensor update - #347 by mikiballester
Summary: the Android 11 updates for the FP3 will no longer be available via the system update on the phone but will require a manual installation.
The necessary files should be on https://support.fairphone.com/hc/en-us/articles/360048050332 but right now the latest A11 file is for 0023.0 and not 0025.0.
Maybe it will just take some time to appear there as well to match the version listed on https://support.fairphone.com/hc/en-us/articles/360048139032-Fairphone-3-OS-Release-Notes#h_01GMTQRVTY2YE5ZNSBP6WXP2AH