Sometimes, when using the find controller to search something in a web page, there is a visual glitch like you can see in this screenshot:
You can try a search on this website in order to reproduce the issue: https://fanglingsu.github.io/vimb/
I am able to reproduce this issue in Epiphany 3.24.2 using webkit2gtk+ 2.16.4.
Thanks to fix this issue.
It's a bug in complex text rendering. There's a rejected patch in bug #148220 that can be used as a starting point for fixing this problem.
*** This bug has been marked as a duplicate of bug 148220 ***