This form shows the issue:
https://pastebin.com/1x4XqiKZ
With all zeroes in the numbers, the checkbox should be visible but isn’t. Possibly related to the whole row becoming hidden when the calculations in the same row are hidden.
Workarounds: Un-hiding the calculations or moving the checkbox to a different row.
P.S.
Both in the forminator GUI and when exporting the form the number fields are still “number”, see this part from the export:
JSON
{"id":"number-1","element_id":"number-1","form_id":"wrapper-8718-4979","type":"number","options":[],"cols":4,"conditions":[],"wrapper_id":"wrapper-8718-4979","calculations":"true","limit_min":"0","limit_max":"150","field_label":"","placeholder":"E.g. 2","condition_action":"show","condition_rule":"all","default_value":"0","required":true}
The HTML as mentioned is however type="text".