What could it be - a site on http flips to httpS?

Question

css

Good day everyone!
Site on http. WordPress. Never done anything related to https.
But lately, strange behavior has been observed.
Completely random, maybe 1 out of 20-30 clicks. When you click on a link, suddenly https appears in the address bar in this link instead of http.
Immediately another person checks - everything is in order. The link opens with http.
What could it be?

Answer 1

wrapper, in it:
input in a frame
on top or next to 2 buttons with absolute positioning and frames

Answer 2

Contact hosting support, they should help.

Answer 3

Chrome or any browser?
Recently encountered similar behavior:
superuser.com/questions/565409/chrome-how-to-stop-...
I.e. chrome always redirected and https:// version.