This problem has only just started happening duriing print setup. While mixing the resin the mixer arm keeps flicking out onto an angle and then struggling to get back in place. There is no issue with the bite valve on the cartridge. Clicking the arm back in place works ok, but then the same error occurs on the following attempt at a print.
See image of final break: Imgur: The magic of the Internet
Please let me know if more information is needed.