I have another topic on the OLED display not handling addressing mode (DA 02/DA 32) properly but this is a different (although could be due to the same error). When in horizontal addressing mode 0x20 00, I’m supposed to be able to limit the Page addresses where data resides, e.g. 0x22 02 05 says to limit any data sent during horizontal mode to page address 02 to 05, which means no data should be sent to pages 00 to 01 or 06 to 07. Similarly, there’s a way to limit the columns that horizontal addressing mode allows data to be sent. .e.g. 0x21 20 5F should limit any new data coming in to columns 32 to 95. But when I send these commands it’s allowing data to be written to all pages all columns…
Please check your code. The way you send data over I²C or SPI should not inadvertently change the addressing mode. You must not send more data than expected.