In the following example, Notation Options > Repeats > Clefs and key signatures in repeat structures is set to Do not track in the first flow and Track in the second flow. The key signature in each flow changes from D minor to C minor in the third bar and C major in the last bar:
The first flow is missing the cautionary flat before the end repeat barline to signal a return to D minor, but the second flow does not have the correct number of naturals to show the change from C minor to C major.
Could you attach the project file please? The behaviour in the first flow looks like what I would expect, if tracking is turned off (i.e. it is the same as previous versions), but it would be good to confirm exactly your settings for the second flow.
Here is the Dorico project:
Problem with cautionary key signature at repeat barline in Dorico 6.2.dorico (1.3 MB)
The second flow is a duplicate of the first flow with tracking turned on.
Right, that natural in the final bar of the second flow isn’t a cautionary - it’s a restorative to indicate that the cautionary at the end of the first-time ending no longer applies. The problem is that there’s a new key signature as well, but the new key signature has no accidentals of its own. We’ll discuss this.
Hi Richatd I do have the same issue with dorico 6.2 can you check and advise Please check the 28th measure there is two sharp cautionary key I cant find a way to hide or delete it.
Menacing Minuet.dorico (2.3 MB)
I’m not sure why, but it works if you move your Fine forward or backward (select it in Write mode and press e.g. Alt+Left Arrow).
This looks like a bug. As Charles says, I think the “Fine” and the start-repeat are getting confused, internally. We’ll take a look.
Thank You Richard and Charls. Let us hope it will be corrected in the next update
Just goes to show that, no matter how well you test, to really stress your software, you need a user. 
I think you need a @johnkprice (and also a @Krish)
The problem I reported in this topic has been fixed in Dorico 6.2.10, and the workaround I gave in this post is now obsolete. Thanks to @Richard_Lanyon and the Dorico team.
