Themes For Clock Doesn't Work!

[WingLT]

Ever since I got the Note 8 themes for the clock don't work on the lock screen that I get from the Theme Store... They show up when I first apply a theme but then a hour later reverts back to the standard clock. I then have to manually chose a color for the clock instead.... It's really fustrating because I never had this problem with my S7 Edge... Is this because it changed with Oreo? Or is something wrong? I tried looking at the settings and didn't find anything....