Auto saving in realtime doesn't wait as expected when the user types during saving

Steps to reproduce:

1. Create a new document
2. Type a first word
3. Wait 50 seconds
4. Type continuously for the next about 20 seconds, and in particular continue typing when you see notifications about saving

Expected result:

A single version is saved after about 60 seconds, and the next version is only saved about 60 seconds later.

Actual result:

Several versions are saved within a few seconds, basically as soon as the first save operation finishes, a second one starts. How many of them are saved depends on how fast you type, it stops as soon as you make a short break, then the next revision only appears about a minute later as expected:

I've reproduced this both on a 17.4.0 installation as well as a development snapshot of today. I've seen this behavior at least since the introduction of the new realtime UI, maybe even earlier.