I'm starting to think there is some incompatibility between Windows and Linux for the blockchain files or the wallet.dat. I am syncing from scratch with a fresh wallet on the Raspberry Pi now, and so far no Problems. I will keep you updated

This is possible. Cause arm cpu and x86 cpu have different byte-order.
Yeah, something like that. My first thought was something with the levelDB, since the error mentioned the wallet.dat. I have wallets for 4 or 5 other coins that I can move between Windows and RasPi without problems, so it seems to be something specific to Terra...