Can confirm this. (was not the case in 2.79)

Can anyone here test the build that @Arto Kitula (akitula) posted to verify if it solves the issue?

Committed second part rB83a7d98a32. Should be all fine now.

Setting to medium though since the error is reported clearly now, it's just missing the additional popup report.
Got an appointment now, will check as soon as I'm back.

Since rB4c20c53b8980 (thx @Julian Eisel (Severin)! ) only partially fixes, will reopen...

@Sergey Sharybin (sergey) : Just a note I have added this to 2.81 milestone (since it was set to "High"), I think you are on it already, right?

@Sergey Sharybin (sergey) : I have added this to 2.81 milestone (since it was set to "High"), mind checking again?

@Brecht Van Lommel (brecht) : I have added this to 2.81 milestone (since it was set to "High"), mind checking again?

@Brecht Van Lommel (brecht) : I have added this to 2.81 milestone (since it was set to "High"), mind checking again?

@Arto Kitula (akitula) : Just a note that I have added this to 2.81 milestone (since it was set to "High")

@Sergey Sharybin (sergey) : I have added this to 2.81 milestone (since it was set to "High"), mind checking?

@Sybren A. Stüvel (sybren): maybe you could check on this?

I dare setting this to High...

The AnimAll workaround probably caused T69509, so I still think this is a High priority...

I hear you :)
Will continue looking at it (as time permits), I also think we should at least iron out the worst bugs 2.8 has compared to 2.79...
[ squashed one yesterday :) rBe52ad1835a6a ]

(1) already asserts earlier now:
BLI_assert failed: /blender/draw/intern/draw_cache_impl_particles.c:1519, particle_batch_cache_ensure_edit_pos_and_seg(), at '!"Hairs are not in edit mode!"'
(Just dropping this here because I have seen in reports elsewhere - hopefully this will make it easier to track down the issue...)

Yes. Sorry about that - the video was a fast load before I was off to my office and I probably screwed it up somehow. It doesn't play here either. Can fix it after I get back to my studio tonight (four hours from now, five allowing for domestic fiddle-faddle...)

I will check T65038.

Cant see the video for some reason...

Going over hair issues atm (to clear the tracker -- but also to have some input on what the next system has to take care of)

Can confirm this.
This might just be a viewport drawing thingie, needs more investigation...

In T69452#768810, @Philipp Oeser (lichtwerk) wrote:

by the way, you won't be able to do that until you comb it, may be a second bug

confirmed as well [it might be better to open a separate report on this]

@Philipp Oeser (lichtwerk):
I'm a bit slow on the uptake, but I'm trying to figure out what it is I'm supposed to be seeing.
There is a sudden, abrupt transform that happens to the hair itself. Almost looks like a shear. Shot mpv-shot0001.jpg is the frame immediately before the transform, and mpv-shot0002.jpg is immediately after. Other than that, the hair dynamics looks pretty much as intended. See my vid_T69265.mp4. That abrupt transform - that's the manifestation of the issue, right?