Not sure if this is what happened in your case, but sometimes when bottled nutes are used if the solution isn't shaken up, it tends to stratify. Meaning the last parts of the container have a denser concentration of fertilizer as they become less aqueous. This causes an increasing concentration of fertilizer and nute burn can result. If that occurs and the last parts of the bottle have a higher concentrate, use less fertilizer and more water when preparing the mix.
Obviously when shaking, make sure the cap is on tight to prevent spills.
I'd begin by flushing that plant. Good luck.