I'm currently posting this with TornTools enabled.
Was camping a friend's attack page for reasons. They self-hosped a few seconds after landing (before land protection expired), their self-hosp expired and I letTorn update the page and they had "Has just landed in Torn" protection still active -> it looks like the self-hosp interrupted the timer and the timer resumed after they left hosp? Don't really know what else would cause that.
I did refresh the attack page while they were self-hosped, and yes have torntools active which has the block allied players feature, but I don't think that'd cause this issue. It's a little too involved to test this myself, I bet it could be recreated using dev tools pretty easily (land -> hosp before timer runs out -> set hosp timer to 10s~ and see if land timer still persists, or something like that).
Pretty certain this isn't an intended feature ;P
TLDR - Landing protection timer is carrying over through self-hosp