Firstly, I'd say that there isn't anything particularly Yoda-like in your examples. Both sentences follow the standard-English [Subject][Verb][Object] ordering rather than a Yoda-like [O][S][V] ordering.
[What][are][the most common native speaker English mistakes]?
[I][was reminiscing about][the Angels game we made the signs for].
However, you are right that there does seem to be a bit of clunkyness in the way you're constructing the noun-phrases for your sentences' objects.
To me, it sounds like you're speaking too quickly and find yourself trapped in a sentence with no way out other than to generate a massive noun-phrase to specify details you had forgotten to include earlier. And, unfortunately, it appears that your reflexes tend to prefer long adjective phrases that inadvertently bury the lede.
For example, lets make your first sentence even more difficult to parse. The object of the sentence is: mistakes in English, made by native English speakers, made most often. How bad can that be to understand?
What are the most common English native speaker made English mistakes?
We're still talking about English mistakes commonly made by English native speakers, but because I've glommed "English-native-speaker-made" together as another nested adjective phrase I'm giving readers/listeners a very difficult job to suss out that "mistakes" is actually the Object they are looking for. Your version isn't remotely so bad as my example, but it still buries your Object behind a mess of adjectives.
The better alternative is to make your object clear early, and then use a prepositional phase to specify those necessary details.
What are the English mistakes most commonly made by native speakers?
Your second sentence could also benefit by breaking out a prepositional phrase rather than making "we made signs for" a direct modifier for game.
I was reminiscing about the Angels game when we made the signs.
Basically, try to break your clumsier sentences into more bite-sized chunks by using a prepositional phrase or two rather than defaulting to chained adjective phrases.