Playback outside of WC, with any file type is not an issue with the M-Audio. It is however, within WC.
I had a strange occurance today whilst recording with the new beta. The recorded file was corrupted by tiny spikes, thousands of them, pointing upwards and down. These spikes were on the written wav, and not from the record, nor were they audible during the recording. The correction widths WC made of these spikes were on a scale from 200 to beyond 500. I didn't know correction widths could go that high.
I encountered this once before in 3.5 with the M-Audio (no s/pdif) when I unplugged a device that used a switch mode power supply while a recording was in progress. From the moment the device was unplugged, the recording became corrupted. Again, it was not audible during the recording - only on the written file.
This time, there is no easy explanation. The only way to fix the problem was to increase the ASIO/WDM buffer size to 512 in the M-Audio control panel. I had hoped this would ease the playback issue in WC but unfortunately it did not.
I don't even know if this incident is related to WC or not, as it has never occured with another recorder. It's occurance is so rare, that fact alone means nothing. Keep in mind the only commonalities with the 2 incidences are WC and the M-Audio - absolutley everything else has changed (except the record player).