Error with expression after pre-comp

[artfullyemma]

The error I see in the expression field is "Error:  Error:  Internal error: "

It worked fine before precomposing... sometimes the error will go away, seem fixed, then appear again for no apparent reason.

Any idea what the error means or how to fix it?

[Mylenium]

Have you actually expanded the little arrow in the warning for more details?

Mylenium

[OussK]

Maybe the issue originally come from the expression that you're using on the Null Rotation so it affects the expression on the text layer, so let us know what expression you use on the null layer 

[Roland Kahlenberg]

This seems like a bug. The strange-looking icon that appears in the Error Message is something I too have seen. Please file a Bug Report and include AEP if you can. This bug appears intermittently and this makes it more difficult to nail down. 

[Rick Gerard]

I have seen this happen with expressions that look at another layer based on time. It happens once in a while when scrubbing but if you preview or render the error goes away. I think it's just a random 'what time is it really' a bug that pops up occasionally when expressions point to properties in another comp.

[artfullyemma]

When I started Ae and opened up the file this morning, the error had disappeared and everything is working as it should. I think the "random bug" diagnosis was correct.