iPad Pro 12.9” Gen 1 on iPadOS 13.5.1 with Minecraft 1.16.0.
Thrown/Shot items such as Arrows, Tridents, Snowballs, and more, do not go between 2 honey blocks. See attached video for setup and replication steps.
Addendum: Prior to 1.16.0 this bug affected both horizontal and vertical axis but in 1.16.0 only the vertical was fixed. This can be seen in
MCPE-58138 even though that report does describe in text both horizontal and vertical axis.
Addendum 2: This bug is different from MCPE-59812 as that bug exclusively describes mob/player movement on top/above honey blocks with no mention of thrown/shot entities in it’s description, any attached documents, or comments too. This bug is exclusively regarding thrown/shot items between blocks not above them.