[old_tv_nut]

Off-air pic is too blurry to see this kind of stuff.

Worth checking grounds, but it's likely the delay line and its grounds are OK, and you are seeing a combination of multiple effects that are normal

Possible contributors
1) using a crosshatch signal generator - signal spills all over the channel, has no phase compensation like a commercial transmitter, transient response varies with fine tuning
2) chroma trap ringing
3) delay line load impedance not perfectly matched, line has some phase distortion not perfectly compensated by the load coils
4) sound trap ringing, made worse by the bar generator splattering a lot of energy into the sound area
5) other IF response effects

(2), (3) and (4) may be within normal tolerance for this chassis, and may be less visible with a properly filtered commercial modulator. VCRs, DVD players and digital TV converters have no video phase slope pre-compensation as required by FCC rules for commercial transmitters. One would hope they had at least luma/chroma delay alignment to match the FCC requirement at chroma center frequency, but that was/is often not the case. (PAL did not use transmitter pre-compensation, intending for any chroma edge distortion to be cancelled by the PAL decoder.)

To separate video from IF issues, turn the fine tuning - if the rings move, it's IF, otherwise it's video (detector, 4.5 MHz trap/take-off, and following video circuits)