“I think this is part of the teachings of the Buddha.Do you see any trouble or any great problems?”
Yes it is mentioned in some Suttas i.e. the Sutta Piṭaka (subject to confirmation).But not exactly with the same language.
A relatively known example is when The Gotama says that one shouldn’t become obsessed by formal practice/thoughts about it if for a reason or another one can’t practice that very day. Then one should let go. Otherwise the wholesome (practice and thinking about the practice) will become unwholesome…
Your post it’s about thoughts-observation but thinking it’s one thing and acting is another…