Fatal error: Nesting level too deep - recursive dependency?

Last Commerce version (1.2.1).
When I try to delete product in Cart I get this …

Fatal error : Nesting level too deep - recursive dependency? in /www/core/components/commerce/model/commerce/comsessioncartorder.class.php on line 225

We’ve not seen that error before, and I’m also not seeing it in my development environment, so please email support@modmore.com with credentials so we can try to debug that for you.

From some googling into possible reasons for that error, it might help to add the third argument on the mentioned file/line:

$pos = array_search($item, $this->_items, true);

… but I would like to understand how it’s getting into any recursion there. I can’t see how that’s possible…