Growing Pains with Newer Strains

I have a couple of issues, I need help with. I am not new to all of this, however, recently added new strains to the hydro gardens. My areas are tended with better care than a hospital and our girls as most...are spoiled rotten. Every time we decide to add some new strains, we have probs. I get the fact that different strains have different needs, but it is frustrating.
Oddyssey is a good producer, nice evenly tight buds. Converted from pebbles to soil a few months back and all was well, in the sterile, well tended environment. New soil each time, trays cleaned..and so forth. Added OG, PK, Big Buddha Cheese, GDP, MK, BubbleBerry, Morning Star, lavendar and Dynamite. All of the sudden, powder mildew...taken care of with peroxide..okay, now, the Oddyssey in veg, has been showing not only the usual, once in awhile Three fan leaves...but One leaf out of the fan...Only one...what the...????
We eliminated all strains prior to Oddyssey, once we got her going strong and then added the new babies...We do it from A to Z, not seeds, cloning...sterile, scrub trays, ph, light, humidity good...But it has been hella hot here....(flower room has air conditioning and veg room, looks good, cept the fan leaves now.....)(no bugs, no signs of root problems or stem issues, no other molds...)
Any help and what else do I need to tell you, for assistance. All help appreciated...more hugs..from me...