Error code 2123-1502 still pops up.
Nintendo previously released firmware update 12.0.3. earlier this week, when some users started noticing problems with the Switch and their micro SD cards. It then got pulled, only to be rolled out again later in the week.
Some people are still encountering an error, with 2123-1502 popping up, which leads to them not being able to download any games from the eShop or update their current games.
As of this moment there hasn’t been any official statement from Nintendo concerning the matter.