Ender pearls sometimes won't work with end gateways

I am unable to reproduce, is it possible that the world just takes a moment to load?

It’s hard to reproduce, but yes the chunks are already previously loaded. And like I said in the description (I don’t know if I described it well enough there but here is me having another go) when you do reproduce this, there is a chance that after you then successfully teleport to the other side the previous ender pearls would still be flying.

I have experienced this problem on 20w19a as well. I threw an ender pearl into a return gateway and did not get teleported. I waited for somewhere between 60 and 120 seconds, while continuing to move closely around the gateway in circles. The server was not under any stress. After those 1~2 minutes I decided to throw another ender pearl into the return gateway, whereupon I was immediately teleported back to the main island–however one of the ender pearls was there, mid-flight, as well. It quickly landed before I could get my bearings and teleported me to where it landed like a normally thrown ender pearl does.

Experienced this again today on pre-release-2. This time I logged out and logged back in between throwing the first pearl and the second pearl. Was met with the same situation of seeing an ender pearl fly and hit a wall, teleporting me, after the second pearl sends me through the portal.

I'm suspicious that the angle I'm throwing the pearl at might be playing a part. Typically I end up aiming such that if it went through the portal it would hit the bedrock on the lower side that is farthest from me, and the pearl almost clips the bedrock on the upper side that is closest to me. And then deviate from the baseline randomly.

This happened to me in 1.16 pre-release 3 while testing with MC-188486. So affects 1.16 pre-release 3

Fixed in 1.16 Pre-6