Bees that are stuck in the beehive longer than they want to (due to a solid block preventing them from exiting) do not keep on ageing.
This commit (https://hub.spigotmc.org/stash/projects/SPIGOT/repos/craftbukkit/commits/062680a826451d77e9b0822b0649809f953be3a0) presumably introduced a partial reset for the `ticksInHive` variable for bees inside the beehive if they fail to exit the beehive to, again presumably, prevent exit attempts on any tick after that.
While this works to prevent the exit attempt spam, it also limits the maximum age a bee can accumulate while inside a beehive and hence breaks vanilla behaviour.
A potential fix would be a split of the two variables into 'ticksInHive' and something like 'ticksTillExit' to allow for both the reduced exit attempts and correct ageing.
Might be the best solution to ensure that any other modifications to the ticksInHive variable is respected.