"estimated_time" on baking right is not constant

Question

Yesterday I noticed that estimated_time on baking rights is not constant. It looks like it changes at the start of every block.

Can someone explain why that happens?

For example:

{estimated_time: "2019-03-21T00:20:30Z", level: 64633}

And then, at the start of next block:

{estimated_time: "2019-03-21T00:23:30Z", level: 64633}

Answer 1

This happens when the network is running late.

This estimated_time is computed on the "every baker at priority 0 will bake" hypothesis.

Each time a block is baked by the baker of priority 1, it is baked later and every following block has to be baked "later"...

Reference

Thanks to @Pierre Boutillier for helping with this