I had 5 slots before so why would I only have 3 now? that is a bug!that's not a bug, your MC would have more slots when you upgrade it further.
Before the change, you had 5 slots total for all three buildings. Now you will have 5 slots for each building, once you upgrade it far enough. This may also require researching all 5 troops to get all 5 slots.I had 5 slots before so why would I only have 3 now? that is a bug!