Midi clock glitch on delay

Hi everyone, I’m having a problem with the MIDI clock on my Tonex pedal and its delays.
The pedal is synced to the Cubase project via a MIDI DIN connection between Cubase and the pedal. Tone X receives the sync correctly, and the delay is in sync with the project tempo. However, when I play the project back, the delay goes haywire; it seems like there’s a glitch or variation. The tempo itself doesn’t change. I have the same problem when syncing directly via USB with another sequencer and with both delays. Has anyone else experienced this issue?