Pro Tools glitches with sampleType = Int24

[dechamps]

Using FlexASIO 1.6, Pro Tools First 2019.6.0, and the following configuration:

bufferSizeSamples = 1024

[input]
device = ""

[output]
channels = 1
sampleType = "Int24"

The audio in Pro Tools is audibly glitchy. The glitches occur when the signal amplitude gets loud, which might indicate the most significant bits in the 24-bit frame are being set incorrectly.

This will also be triggered by FlexASIO autoselecting the Int24 sample type when using WASAPI Exclusive.

I am unable to reproduce in FlexASIOTest or other ASIO applications.

[dechamps]

I can also reproduce in latest Pro Tools 2020.9 (which just came out).