This error seems to be connected with the update to version 5.36 as it just appeared after that.
When editing an existing membership or adding a new membership the following error appears in the logs:
TypeError: Argument 1 passed to CRM_Financial_BAO_Order::setOverrideTotalAmount() must be of the type float, string given, called in C:\wamp64\www\civicrmd8\httpdocs\sites\all\modules\civicrm\CRM\Member\Form.php on line 486 in CRM_Financial_BAO_Order->setOverrideTotalAmount() (line 152 of C:\wamp64\www\civicrmd8\httpdocs\sites\all\modules\civicrm\CRM\Financial\BAO\Order.php).
I feel it could be connected to https://github.com/civicrm/civicrm-core/pull/19476/files
A quick fix I found was to change line 486 of civicrm/CRM/Member/Form.php from
But I am not quite sure if this really solves the issue or what sideeffects I do not see. Maybe this type casting should be done earlier in the process? or maybe the problem lies somewhere else? In my case the value of $formValues['total_amount'] is an empty string but I do not know where this value comes from.