I am sorry for this delayed reply to your gardening question. We are transitioning to a new Q&A system and your question was unfortunately lost in the transition. I have discovered it now and hope this reply is not too late to be of help.
Your bougainvilleas are indeed acting rather strange. However, it is not unusual for that plant to drop leaves when subjected to soggy wet or dry conditions. I wonder if the pots are drying out too much or if the drainage is still not good despite the extra holes (unlikely).
Other than watching the water I don't know anything else to suggest. Since they appear to be growing well I would just wait and watch. Hopefully they will stop this nonsense and settle in and grow right!
Cycles of bloom is common on most bougainvillea varieties.
Thanks for the question. Please stop in again soon!
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