I suspect that if a patch that targets multiple bugs gets merged, the corresponding WMF-deploy tag is only applied to the first phab ticket, not the other ones. Example: T146400 (I had to manually add it)
@Jdforrester-WMF I think the above is a frequent mistake, so we could either spend a lot of effort educating all of the developers, or we could update the script to allow both forms. I suspect the later is easier. Reopening to get some feedback from the Release-Engineering-Team about complexity of doing this.
This was and is documented: "If a patch resolves two or more bugs, put each Bug: T12345 reference on its own line at the bottom."
I strongly doubt it's a frequent mistake.
@Yurik: As you want feedback from the Release-Engineering-Team, I assume you plan to contact them.
Note that there's also https://www.mediawiki.org/wiki/Commit-message-validator which is currently only installed for VE-MW (and non-voting at that) but will spot and V-1 mis-formatted commit messages.