After bedrock players dismount a horse (in this case, they were traveling quite a distance) the horse will die for seemingly no reason. It happens regardless of bedrock platform but is fine for java players. The player in the attached issue was on Xbox Series.
The server is running the following versions of plugins:
Geyser 2.9.0-b976 (git-master-a5db510)
Floodgate 2.2.5-SNAPSHOT (b121-55a85ec, master)
Server is PaperMC 1.21.10 (build 100, main@e8c6ba5)
Dump: https://dump.geysermc.org/tVpvz2XE9qUCUv65HRiIoCf5vd2oSCxX