The problem was observed in textproc/dikt.
Before r469254 this port had
When in this condition PORTVERSION was changed to
> $ portlint -C
> FATAL: Makefile: dikt-2.s1 < dikt-2l3_2. Choose another PORTVERSION or bump PORTEPOCH.
> 1 fatal error and 0 warnings found.
This is wrong because 2l3 < 2s1.
There are very few versions in this format, but it looks like portlint doesn't handle them correctly.
I'm closing this as not a bug.
The bug was in the port using DISTVERSION to begin with.