This morning, the ambient humidity had increased to 33% RH, but all of the readings inside the case were same as yesterday. So, I opened the case for the first time since Jan 13th, removed the Dampit style humidifiers, and closed the lid. As suspected, both humidifiers were dried out.
An hour later I checked the humidity and it didn't budge. Will check again later today and update the post.
UPDATE: 12 hours later the ambient humidity has increased to 35% RH, but the case readings are unchanged.