If you try to use the setting for input mask, on a repeater form field it just doesn’t work. There is no error, or message. It’s up to you to find out why it’s not working. Eventually you end up looking at the “Known Limitations” on the GF Repeater Forms page at the bottom. Then you hire a programmer to fix it for you. Then when you update the GF plugin the fix doesn’t work anymore, so you hire another programmer (the first one is unavailable) to fix it again.
Apparently it’s not too hard to fix. But version after version of GF still has this limitation. I really feel like you guys owe me more than I am paying for the licence, because of your failure to at the very least remove the option from the settings so I don’t waste my time figuring out why it doesn’t work. But really you need to just fix it.