pgAdmin error with new PG15 servers: argument of type 'Response' is not iterable

Hello All and Happy 2023.

We're in the process of upgrading our Postgres instances from 13/14 to 15.1, and have done a few already. However, pgAdmin is tripping this error when attempting to extract DDL for a schema...but only in the new PG15 databases. It works just fine with the other versions. This seems to be the only gotcha we've encountered at this point.

So far this has eluded me, and searches have been unsuccessful.

Details:

Version 6.18
Application Mode Desktop
NW.js Version 0.71.0
Browser Chromium 108.0.5359.95
Operating System Windows-10-10.0.19044-SP0

The error shows up in the pgAdmin log as such:

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2023-01-04 14:47:36,313: ERROR pgadmin: argument of type 'Response' is not iterable
Traceback (most recent call last):
File "C:\Users\stm\AppData\Local\Programs\pgAdmin 4\v6\python\lib\site-packages\flask\app.py", line 1517, in full_dispatch_request
rv = self.dispatch_request()
File "C:\Users\stm\AppData\Local\Programs\pgAdmin 4\v6\python\lib\site-packages\flask\app.py", line 1503, in dispatch_request
return self.ensure_sync(self.view_functions[rule.endpoint])(**req.view_args)
File "C:\Users\stm\AppData\Local\Programs\pgAdmin 4\v6\python\lib\site-packages\flask\views.py", line 84, in view
return current_app.ensure_sync(self.dispatch_request)(*args, **kwargs)
File "C:\Users\stm\AppData\Local\Programs\pgAdmin 4\v6\web\pgadmin\browser\utils.py", line 311, in dispatch_request
return method(*args, **kwargs)
File "C:\Users\stm\AppData\Local\Programs\pgAdmin 4\v6\web\pgadmin\browser\server_groups\servers\databases\schemas\__init__.py", line 233, in wrap
return f(*args, **kwargs)
File "C:\Users\stm\AppData\Local\Programs\pgAdmin 4\v6\web\pgadmin\browser\server_groups\servers\databases\schemas\__init__.py", line 930, in sql
self.format_request_acls(data)
File "C:\Users\stm\AppData\Local\Programs\pgAdmin 4\v6\web\pgadmin\browser\server_groups\servers\databases\schemas\__init__.py", line 355, in format_request_acls
if aclcol in data:
TypeError: argument of type 'Response' is not iterable

________________________________

And it shows up in the PG log as such (some details obfuscated):

2023-01-04 14:47:36.319 EST,"<role>","<instance>",53334,"<ip>",63b5d7d7.d056,4,"SELECT",2023-01-04 14:47:35 EST,113/106,0,ERROR,42725,"operator is not unique: unknown || ""char""",,"Could not choose a best candidate operator. You might need to add explicit type casts.",,,,"SELECT

I feel like I'm missing something basic here, but it hasn't hit me yet. Hoping somebody here can set me straight. Please do let me know if you need more details.

Appreciate it,
Steve