No, I'm not a native speaker but I have a fairly good ear for colloquial usage after 22 years in my bilingual home and constant exposure to native speakers from all countries.

The insertion of a gratuitous "de" is not unusual. Sometimes it is just typical of colloquial or alternative usage. For example: "Es lindo" vs. "¡Es de lindo!" Perhaps someone can explain this better than I, but it just has a different "feel."

This could also be a case of hypercorrection, since the "de" would be necessary for other verbs in the same context. For exmaple:

Mira de lo que te escapaste.

Here the "de" is necessary, since "escaparse de" is the common formula for the verb.

And finally, Spanish speakers sometimes throw in a totally unnecessary "de" as part of the so-called vice of "deísmo," as in "sabe de que," "pienso de que," etc. This could be an instance of that commonly-noted problem.

For "correct" Spanish you could drop the "de."

Hope this helps.

Alan