I basically was messing around in the new snapshot, and I came across this bug. When I set the randomTickSpeed to a high level (I used 10000) the furnace stopped.
MC-57838
When randomTickSpeed is on a high level, Furnaces stop working.
Resolved
Duplicate
0
Matt Chaney
(Unassigned)
Unconfirmed
Minecraft 14w25b
Retrieved
Is this still a concern in the current Minecraft version? If so, please update the affected versions in order to best aid Mojang ensuring bugs are still valid in the latest releases/pre-releases. If this has been done, we can reopen the issue.
Keep in mind that the "Resolved"-Status on this ticket just means "Answered", and that we are waiting for further information on whether this issue still exists or not. We will reopen it as soon as the requested information has been delivered.