drastic ph shifts can cause warped growth (varying rates of growth over time). Looks like a suboptimal root zone too. Is that mud, peat and a sprinkle of perlite? Consider doing somethign different for rootzone.. more perlite.. better drainage and aeration. Super heavy, super saturated is not the best option, unless my eyes are deceiving me with your pictures. If it's light and fluffy, that's fine, but coudl still be a pH issue. Easy to rule that out without doing anything too intrusive.