Thunderbolt display video cutout when using Apple adaptor

I am running an Apple Thunderbolt display onto an M2 Studio via the relevant Apple-branded Thunderbolt to USB-C adaptor. Just recently the video has been cutting out intermittently. Investigation suggested that the M2 Studio was 'losing' the display, as if audio was playing through the display, it reverted to the M2 internal speaker.

I have replaced the adaptor, to no effect. When the video cuts out, wiggling the Thunderbolt plug in the adaptor's socket often restores it, so it may be a fault with the Thunderbolt display's lead or plug.

Has anyone else encountered this? Sending the display for repair would leave me offline for an indeterminate period, and I'd prefer to avoid the £1500 replacement cost if at all possible.