A “sort-of error but maybe something that’s so marginal or baked into existing interpreters that it’s not worth changing”:
§1.1.4 states that the maximum size of version 6-7 games is 512kb. However, the addressing scheme of these games technically supports up to 576kb if the routine pointer R_O does not overlap the 64kb of low memory at all (for a total of 64kb low memory + 256kb routines + 256kb packed strings). This is confirmed to be the intended design in Infocom’s YZIP documentation, which states under “Program Structure” that:
(I’m not aware if any existing interpreters actually impose a 512kb limit, but I wouldn’t be surprised to find one that declares a static 512kb buffer to hold the game file.)