Thanks Sai. I got your communucation and was able to work through it. It took about half an hour of signing out of chrome, turning off extensions, using the developer tool to clear the MYOB cache and hard reboot and none of that worked. I then went into the chrome settings/privacy and security/third party cookies/see all site data and permissions. I searched for MYOB and deleted all the cookies that came up. That worked! I've signed back into chrome and turned my extensions back on and it is still working.
So it appeared to be a cookie rather than a cache issue.