05 Subaru Legacy GT Starting Issues

This past monday morning I got in my 05 Legacy GT w/ 82,000 miles. When I turned the key it acted as if the starter engaged for a second then disengaged and made the typical motor winding sound. I tried it several more times with the same result. So I reluctantly called my local repair shop and had it hauled over for what I thought was possibly a bad starter. The mechanic went out to check it to see what it was doing and when he did, it started right up……so WTH!!! He said that when it started it ran as if it had been flooded for a minute or two then cleared up. Throughout the day he drove it around and started it about 20 times and said it “appears” to be ok. It’s a small shop that I trust with my other cars but they don’t have the tech to pull codes on a subaru. So my question is, has anyone else seen anything like this and if so, what was the cause of your issue? Neutral Switch? Cam Sensor? or a Fluke?

What does starter engaged mean and then disengaged?

When you turn the the key(cranking) does do you feel the engine turning/spinning? Or during the cranking period sometime was the motor turning/spinning and then stops and you hear a whirring noise instead. During cranking whirring of a motor instead of the engine turning/spinning means a starter issue.