I have a doubt with the usage of 'durchbrechen'. It is one of those verbs that can be either trennbar or untrennbar. I believe it has the same meaning, but has mainly a nuance between the literal vs. the figurative way to use.
For example, in www.dwds.de I found:
(1) Sein altes Wesen, seine wahre Natur brach durch.
(2) Der Düsenjäger hat die Schallmauer durchbrochen.
My doubt results in seeing that in both sentences above the use is metaphorical, but one is separated and the other is not. I realize, however that if (1) were to be written in perfekt it would be (Sein altes Wesen, seine wahre Natur ist durchgebrochen) and not 'hat durchgebrochen'.
When do you make it trennbar and when untrennbar? Is there a logic to it really?