People on app only are reporting being unable to train on the 3 buildings. Sometimes for me collecting on the app, except barracks, of course, bugged thoroughly, doesn't free one slot but works fine on browser.
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!