I have a choice field with check boxes with multiple selection, but when i select multiple, my controls jump around. I have written rules for hiding the controls for the first time you open the form. Please refer the below screenshot for your reference.
If i select one check box, i don't have any issue
This is how it looks in design view.
I have created new list and created/applied same rules, it works well with one row, if you add new row, from there, the controls are jumping around, please refer the screenshot, i hope there is an issue with "repeating section" with dropdowns inside.
design your form controls hierarchically as follows
apply formatting rules to show/hide single dropdown on panels marked with asterix
make sure none of controls overlaps