I've deployed some troops into the town of an alliance-mate and when I look at the town view I see this:
You can see that there are two buildings under construction where there should be only one. I'm guessing my alliance-mate has Ikariam Plus enabled and one is in the build queue, but that is not consistent with what I see when I queue multiple buildings in my own towns. Refreshing did not resolve the issue.
Browser is Google Chrome Version 145.0.7632.160 (Official Build) (64-bit) on Windows 11 fully up to date.