I had an update panel within the Sharepoint where the trigger is set to PostBackTrigger. Any button within the update panel triggered the click event only the first time. After that the click event never got fired until the whole page is refreshed.
This scenario was working in our test environment but doesn't work in our client's test environment. The difference is somewhere with the sharepoint setup.
To do this, you may need to register a client startup script which disables this workaround, in addition to resetting the default form action: