Donkey Kong Country 2 and Open Bus

I have to say as a 6502 assembly programmer I have wasted many hours of my life tracking down the same issue in my code (forgetting to put an # in front of an immediate value and thus accidentally doing a memory access instead). Often it's like this case too where things might accidentally work some of the time.

Worse than the floating-bus in this example is when it depends on uninitialized RAM which is often consistent based on DRAM so the code will always work on your machine/emulator but won't on someone else's machine with different DRAM chips (invariably you catch this at a demoparty when it won't run on the party machine and you only have 15 minutes to fix it before your demo is about to be presented)

Was there ever an architecture that used dynamic memory with a 6502 CPU? In my (limited?) experience, that platform always had static RAM.