Why flush , then transplant? It is a bit like having a bath before having a shower.
To me it looks like a simple magnesium deficiency, nothing more, which can be solved quite easily and quickly, a couple of doses and success.
By the way, true nutrient "lock out" does not occur until the soil is under 5.5 or over 7.5, which is a highly unlikely scenario if growing in any type of quality soil mix or without doing a major stuff up by applying gallons of an extreme nutrient product.
If your soil pH is anywhere between 6.2 and 7.2, your plant will thrive.
Hope this helps, Organoman.