I had a field called "Year Started" with the slug "year-started" inside a repeatable custom post field group. It was of the type date. I removed it and re-added it under the type "Numeric".
After I did that and saved the repeatable field group, all of a sudden, the slug of that field group changed from education to education-2. Which obviously broke all my views and CRED Forms.
It seems that a completely new field group was created instead of the existing one being updated. I am not able to find the first one within the UI.
Unfortunately I cannot grant access to the website, but I am willing to help track down this bug to any extent that you require.
I tried to reproduce this on the current betas but could not, although it did through up one issue while testing.
You are not using the current Types beta (3.0-b1).
The issue I found was that you could re-use the same slug for a custom field added to a repeating field group if you deleted one and then added another without first saving the field group, but if you saved the field group in between you get the customary warning message that you see in the screenshot, which I have reported.
In neither case was the slug of the repeating field group changed, so I think that must have been a bug with a prior beta version.
By the way, I should make sure you are familiar with the Post Field Control button that you see on the page listing your custom field groups (see screenshot), although it's not new.
From there you can completely remove any reference to a custom field and clean the data from the wp_postmeta table, so that you can re-use slugs when adding new fields if they have been used before.