Qt Installer insists on installing 5.11.2 snapshot

(I think it's 3.0.1 - I can't find its version anywhere except the Finder's Get Info window. It's up to date.)

• run maintenance tool
• choose "Add or remove components"
• deselect all new things (Qt 5.11.2 snapshot)
• deselect an old version of Qt to remove it
• click Continue (it says it's going to use 3.68 GiB of space)
• click Update

It starts installing 5.11.2...

Result: I cannot remove an old version of Qt. (Maybe it would after installing 5.11.2, but I don't want to install it.)