HPCC is 75% peat, I would want to know in soil ph as peat can get quite acidic without proper buffering. This would explain strange leaf mutations and strange growth patterns.
How long until you plan to transfer outdoors? A double transplant is not advisable. However, if you decide to go that route, look into a 1l pot with heavily perforated or cut openings, inside of a 2nd 1l pot. When it comes time for the outdoor transplant, you just slide off the 2nd 1l pot and plant directly into prepared outdoor hole.
You got it - not genetics but medium.
If you haven't, introduce a feeding regimen.