Can’t update from 10.14.3 because my system is HFS

I get an error when running the update, something like “can’t update Because your system is not APFS”.

At first I was like, “WTF? I know my system is APFS because I did a clean vanilla Mojave install about two months ago.” Then I remembered that a month ago I updated my SSD from 512GB to 1TB and used CCC to do it. I assumed all was well because everything seeming works just fine.

Is it possible that CCC cloned my APFS system onto a bootable HFS system? I didn’t think Mojave worked with HFS but obviously it does because I have it!

From what I’ve been googling I don’t think I can convert because the option is greyed out when I boot into recovery mode and attempt conversion to APFS using disk utility.