redstone lag 1.8.3

I noticed in a SINGLEPLAYER world that buttons and pressure plates were acting very slow...
so i went into a different world (in creative) and tested it out. the results are as follows:

1.8.3:
wooden button (floor):
2.5 seconds

i went to go to the last non-snapshot that was stable (1.8.1) and did the same on the SAME button:

1.8.1:
wooden button (floor):
1.5 seconds

I believe this is an error, as I didn't get any lag (I got 50+ fps)