Not sure if this error could be affecting this behavior... This seems to come from a 3rd party plugin (getwooplugins-form??).
Anyway, I suspect this could be due to some kind of conflict with any 3rd party plugin you have active. In order to determine if this is really the cause, I'd try to disable all your plugins except WooCommerce and ATUM and check if it works in that way. If so, you can start enabling them one by one and trying until you found the source. If possible, I'd recommend doing so on a staging site.