So, I made dots on my cookies with RI, and when they dried, I noticed the middle of the dots had sunk in. Why did this happen?
Been discussed for years on here. It's just a "support" problem, not anything to do with air bubbles in your icing or anything. The dots and larger piped areas "cave in" per se when they dry.
One solution is to slightly thicken the icing you are going to do detailing with, another is to do the "sinking" technique where you pipe the background in one colour and then immediately switch to another colour to add details. They "sink" into each other and the look is clean, smooth and professional. (One hint though, your two shades of icing colours should come from the same batch so that they won't run/bleed and they sinking into each other neatly.)
It's also great because you save lots of time waiting for one shade to dry before the other can be applied.
Here's an example of the technique:
I recently had that happen with my last few batches of RI. But it wasn't just the dots, there were areas in the outlines that sunk in as well. It never happened before these last few batches so i don't know what happened.