As we previously reported, Chase recently left a scathing voice mail for Harmon after the producer led a "F**k Chevy" chant at the season wrap party.

Now, sources who work on the show tell us ... "What Dan Harmon did was f**ked up ... Chevy is a pleasure to work with."

We're told ... many people on set feel the "dispute" that took place between the two men during the taping of the season finale was blown out of proportion by Harmon ... because Chevy was "very respectful."

Here's how we're being told it all went down -- Chevy had an issue with one of the scenes and asked for a rewrite. We're told Chevy was very calm and polite ... but told producers he would "respectfully decline" to participate in the scene unless a change was made.

Producers shot down Chevy's request ... and he quietly left the set without incident.

Our sources tell us they felt the issue had been handled privately because Chevy showed up at the wrap party ... and everyone was shocked when Harmon grabbed the mic and unloaded on the actor.

One source tells us, "What Dan did was embarassing and left a sour taste in all of our mouths ... so low class."