Powershell Monitors Unknown, "Failed to deserialize probe settings"

We've been using HolyGuacamole's/antonis.athanasiou's Dell Server Storage Hardware Health script for about two years now without any problems. Last week, we updated everything to do with our NMS, migrating to: MS Server 2016, SQL 2016, Orion Platform 2018.2 HF5, NPM 12.3, SAM 6.6.1 (10/31/18 Edit: Updated SAM to 6.7), and setting Orion to HTTPS instead of HTTP.

Almost everything transferred over unharmed except for these Dell HDD monitors. Whereas they used to just work, now they're all constantly flapping between being in an "unknown" state and being "up". If I test the script from the template, it'll work fine 100% of the time.

The error it throws in the application's detail page is

Unexpected error occurred. Failed to deserialize probe settings, probe skipped. Original Exception message is: Cannot access a closed file..

and in C:\ProgramData\SolarWinds\Logs\APM\ApplicationLogs it shows

[STP Pool:66 Thread #1] [C23522] ERROR SolarWinds.APM.Probes.ProbeBase`1 - Failed to deserialize probe settings.

System.ObjectDisposedException: Cannot access a closed file.

I haven't found many hits on this, but I've tried what I've found, which includes:

- Unassigning the application template from all devices, then reassigning it

- Adding [System.Net.ServicePointManager]::ServerCertificateValidationCallback = {$true} to the scripts

- Changing HttpClientHelperSettings RetryCount - I didn't go through with this because none of the options mentioned in that post were in my config file, so I figured it was depreciated.

- Running the configuration wizard to remove the Check for Publishers Certificate Revocation option - This option wasn't in my configuration wizard

Any ideas what's going on here?

Thanks

SW Dell Storage Hardware Health 1.2 error.PNG