In common anecdotal experience with disassembling code, it is very common for data areas interspersed with code (like string literals) to disaassemble to instructions, momentarily causing the human to be puzzled: what is this repetition of five "or" instructions doing here referencing registers that would never be arguments?

The reason is that the opcode encoding is very dense, and has no redundancy against detecting bad encodings, and usually no relationship to neighboring words.

By that I mean that some four byte chunk (say) treated as an opcode word is treated that way regardless of what came before or what comes after. If it looks like an opcode with a four-byte immediate operand, then the disassembly will pull in that operand (which can be any bit combination) and skip another four bytes. Nothing in the operand will indicate "this is a bad instruction overall".