We rolled our walls with SW Duration Flat light gray paint (over existing flat builder grade) several months ago. We had to fix a bubble in the wall (bad drywall patch). Rolled this spot to touch up. The paint was a bit shiny, (have never had this happen on any touch up) about a week later we re rolled the entire wall so it would all blend. The same touch up spot is still shiny. How is this possible? Same paint was used and stirred well along with same roller rolled by the same person. The rest of the wall still looks good and the same, but didn’t lay flat over the shiny spot.
The Lime in the patch causes this “shiney” surface… you need to Spot Prime the area with Pigmented Shellac Sealer Primer… then try local touch up with the flat finish… or redo the whole wall… Note: Using a sheen finish, like semi, satin or gloss will not require this spot priming… Good Luck!