Hello,
The issue you have is related to the J4 routing.
We have to perform tests in order to propose a patch which will solve your solution without moving the issue somewhere else.
In the meantime, we can propose you to override the view "serial / consume" and replace the line
<input type="submit" class="btn btn-primary"/>
By
<input type="submit" class="btn btn-primary"/>
<input type="hidden" name="ctrl" value="serial"/>
<input type="hidden" name="task" value="consume"/>
So the "ctrl" and "task" values will be sent to the router and it will avoid the mixup you have in your case where Joomla think the task is the controller.
Regards,
PS : Please understand that we're in the weekend and it's generally day off for our support team who also need some rest