Steps to reproduce:
Create a superflat world.
/setblock 10 -51 10 stone
/setblock 5 -54 6 stone
/setblock 6 -54 5 stone
/setblock 5 -54 5 cobweb
/tp @s 9.701 -50 9.701 135 50
Press and hold sprint, jump and forward button at the same time.
Observed result:
You will be slowed down by the cobweb.
Expected result:
You won't be slowed down by the cobweb since it's blocked by the stone.
Notes:
Happens since 24w33a.
Maybe related to MC-92875.
It could only be reproduced consistently on -X -Z axises. On +X +Z, it won't work. On +X -Z or -X +Z axises, it is inconsistent.
This is not MC-275298. That issue is remarked as "fixed" and I can confirm.