==== What is the problem?
If I use Special:InvestigateBlock to block `192.168.121.180/29` and use the `Leave a notice on User/User Talk page` functionality, the notice is posted on `User/User_talk:192.168.121.180/29`.
The normalised version of that IP range is `192.168.121.176/29`, so perhaps `User/User_talk:192.168.121.176/29` is where the notice should be posted.
==== Steps to reproduce problem
1. Go to Special:InvestigateBlock
2. For target, enter `192.168.121.180/29`
3. Add a Reason
4. Check `Leave a notice on User page` and enter a message
**Expected behavior:** The message from step 4 is on `User:192.168.121.176/29`, since this is the range that is actually blocked (e.g. see Special:BlockList).
**Observed behavior:** The message is on `User:192.168.121.180/29`.
**Wiki(s):** MediaWiki 1.36.0-alpha (ed5d593), CheckUser 2.5 (1309125).
==== Screenshots (if applicable):
Notice posted on User:192.168.121.180/29:
User:192.168.121.176/29 without notice: