On (some) Comware based (your is not Comware based, it's ProVision based), AFAIK, globally disabling Jumbo Frame capability (which is enabled by default) requires the Switch to be rebooted.
On involved ports, did you try to verify via CLI the Jumbo Frame still appears as enabled or not? if the command was successful but the Jumbo appears still enabled instead of being disabled maybe a Switch reboot is required for that setting to change effectively.
A look at Switches' configurations (especially the section regarding ports used for inter-Switch trunking) would be benefical plus providing more informations about your exact network topology (at least inter-Switch links) and Switches' software status.