Interesting.
MC is trying to check the free space in "\\AUX-Data\My Music\Podcast\" and can't because it doesn't exist.
I expected the setting under "Options > File Location > Audio (CD rips and Podcasts)" to be at fault. I've never downloaded Podcasts onto this PC I am using, so I still have the basic value of "F:\Music\" for that setting, which is where my CD Rips go.
Looking further, I see that there is indeed a setting for Podcasts under "Options > Podcast > Podcast Directory" which is set to "C:\Users\[UserID]\Music\Podcast\", which I have never set. In fact, when I click on that setting to check it, MC drops the "Browse for Folder" dialogue back to "C:\Users\[UserID]\Music\", because the "C:\Users\[UserID]\Music\Podcast\" directory doesn't exist, and that dialogue only allows a user to select an existing directory, although a user can also create a new directory and then select it.
So Cebalaw, the fix for your issue is simply to change the "Options > Podcast > Podcast Directory" setting to a valid existing directory, and MC will check that new directory for free space and complete the task. That should allow your hard drives to sleep.
EDIT: It looks like you found the problem. Now that you have changed the "Options > Podcast > Podcast Directory" setting to "\\AUX-Data\My Music\", has that error gone away? The setting would have changed when you clicked on it, and if you clicked OK to exit the dialogue, it should have saved and fixed the issue. You will have to check again if the QueryFullSizeInformationVolume task is still happening for the "\\AUX-Data\My Music\". That could have been happening because of the Podcast directory issue.
I have no idea when that "Options > Podcast > Podcast Directory" setting was added to MC (couldn't find it in the Release Notes back to MC19), but I think that it is in the wrong place. It is inconsistent with using the one central "File Location" group of settings, which makes such settings so much easier. Also, the fact that it defaults to a non-existent directory, which MC then tries to use at least to check free space, is a bit of an issue. Some refinement may be a good idea. The name of the "Options > File Location > Audio (CD rips and Podcasts)" setting at least will also need to be changed, if in fact podcasts are no longer downloaded to that directory.