Some instructions such as "LD C, A" and others that have to do with the C register don't assemble properly. For example, LD C, A becomes LD C, $00 after clicking Apply. This causes the byte count to be wrong and actually overwrites one byte of the next instruction.
In this image I opened the assembler without making any changes:
Additionally, if you select a few instructions, then edit them with the assembler but don't completely fill up the byte count, it overwrites the "unused" bytes with EA.
Some instructions such as "LD C, A" and others that have to do with the C register don't assemble properly. For example, LD C, A becomes LD C, $00 after clicking Apply. This causes the byte count to be wrong and actually overwrites one byte of the next instruction.
In this image I opened the assembler without making any changes:
Additionally, if you select a few instructions, then edit them with the assembler but don't completely fill up the byte count, it overwrites the "unused" bytes with EA.