Observer Clocks have different behaviors in 1.14.1 pre 1 than in 1.14, a bog standard observer facing observer clock in 1.14 has a timing of 1 redstone tick every 3 redstone ticks, in 1.14.1 it is 4 redstone ticks every 6 redstone ticks.

In addition, observer with redstone dust on it facing dropper which is then powered and unpowered in 1.14 acts as a clock, in 1.14.1 pre 1 it does not.  Attaching screenshots.