The before 1.19 villager iron golem last seen timer was 30 seconds (600 ticks).

In 1.19 and 1.19.1 pre-releases the timer is 35 seconds (700 ticks).

It appears that the spawn attempt countdown timer is resetting before the last seen golem countdown timer is finishing resulting in the villager waiting for the next spawn attempt, or another 100 ticks.

This appears to be a bug in the calculation order.

A youtube video showing in more detail.

https://www.youtube.com/watch?v=DehjbNoEY30

You can easily recreate this bug by using a repeating command block to kill golems as soon as they spawn and timing the time between spawns.

Code analysis

Code analyses by igoticecream can be found in this comment and this comment.