Intermittent Request Failure with RDC endpoints - banno-digital-toolkit

Question

We've been doing some testing with the RDC endpoints in Banno and noticed a bizzare issue where, intermittently, a POST request will respond with a 400. Seconds later, submitting the same request will yield a new RDC account as expected. I'm doing my testing in PowerShell, and below are some examples.
New-RDCAccount -userId $userId -accountTypeMarker Checking -name "Text" -accountNumber "XXXXXXXXX"
And the response for this would work, however when I send a request minutes later:
New-RDCAccount -userId $userId -accountTypeMarker Checking -name "Text" -accountNumber "XXXXXXXXX"
#Note that $userId is the same throughout each request
I get this response: The remote server returned an error: (400) Bad Request.
I understand that the error code implies that my body is malformed, but how is it possible that in one request it's acceptable and in the next it's malformed?
Below is the body for each request (with redacted information). The first one is a working example, and the second one is the failed example:
{
"accountNumber": "XXXXXXXX",
"accountTypeMarker": "Checking",
"name": "Text"
}
{
"accountNumber": "XXXXXXXX",
"accountTypeMarker": "Checking",
"name": "Text"
}
Because I feel this issue is a little hard to believe, I've provided screenshots as well with this.
Not working:
Working:
I'm hopeful someone here can help me out here, cause I feel like I'm taking crazy pills looking at this.
Thank you!
Edit:
Here's another example of it working on one instance, and not another with 0 changes to the code (side by side):
Edit of edit:
I can replicate this issue pretty consistently through Banno People AND my own PowerShell script. I feel this is definitely something on the Banno side at this point...
Pictures for Jamies comment:
Working request headers:
Fail request headers (Note that accessing any of the elements yield a null result):
I'm using this endpoint: https://jackhenry.dev/open-api-docs/admin-api/api-reference/v0/rdc/details/#/User%20RDC%20Endpoints/post_a_mobile_api_v0_institutions__institutionId__users__userId__rdcAccounts