[old_tv_nut]

Do you have the service manual for the set? The published order of convergence adjustments is usually designed to prevent ending up with an excessive error in one area of the screen. Rectangular tube horizontal dynamic waveforms usually consist of the same horizontal rate parabola and sawtooth waveforms as a round tube, plus a higher frequency adjustment that affects things halfway between cneter and edge. Your picture looks like MAYBE you have walked the adjustments into a state where the horizontal rate adjustments are not not really right but are being compensated by the higher frequency adjustments from center to halfway out, and beyond that distance the compensation is wrong. (Or something like that, anyway.)

In other words, MAYBE adjust the H parabola so the blue is less low at the edges and slightly high halfway out, then adjust the high frequency to cancel it in both places.

Sorry I don't remember what names they put on these adjustments, just what the waveforms do.