We have code for our ajaxified submit forms to disable the submit button on request start and re-enabled it on request end. This used to work, but when we upgraded to the latest build (2020.2.617), setting the disabled property to false now throws an error in IE from the WebResource.axd file (does not appear to have a problem in Firefox). The attached demo project shows exactly where the error occurs. Just click the Search button.
Attached picture shows an example of the error message thrown. The error does not appear to be with our javascript code itself; all the variables are populated and valid. It looks like something is getting triggered in the WebResource code when we set the disabled property to false and that is where the break is occurring.