What kind of issue do Mataro Blue have ?

Transplanting an already stressed plant isn't a good idea even tho I hardly notice a slow in growth, I guess trick of the trade after so long. No drainage is the biggest nono. Water pulls air into the soil when watered, with no drainage this can't happen and slowing killing your roots off because they can't breath so to speak... saturated, wet-dry cycle is life or death of a plant.. Good luck.

I have had a look at your diary too. Probably transplant and training has slowed her down a tad. Would have been better transplanting then waiting for her to establish herself in the new pot before any heavy training. She should be OK over the next week.

Red it wrong. You transplanted 2 times in a week by your diary. This was hard on the plant. Stripping it down of foliage and topping was hard on the plant. It will take some time to recover from these events, at least 2 weeks before she starts to grow normal again. Give her time and have patience. It’s not good to strip a plant of all its leaves, it has nothing to carry out photosynthesis when you do.