Each time an operation is performed, the editor creates a backup copy for quick undo. By default, the number of undo levels is unlimited. You can set a limit on undo levels or change the disk for temporary files.
The internal clipboard in the editor does not require copying data between open files; it is enough to transfer only timestamps. This provides zero latency during editing, but this format is not supported by third-party applications.
This looks like clipping due to the fact that some of the samples are outside the acceptable range. Either save files in 32-bit floating point format, or do volume normalization before saving.