@bootrec In 2020 you weren't running macOS Monterey, or probably even Big Sur. If you've still got a Catalina system available try your old process there, and if it works you'll know you're fighting a macOS change and perhaps it's time to look at using a script as a .webloc is simply a .plist file with a different extension, and all you'd need to do is write the contents of the plist. Here's an example script that writes a .webloc for this Jamf Nation thread:
#!/bin/sh
# Write Test Webloc.webloc to current user's Desktop folder
currentUser=$(/bin/echo 'show State:/Users/ConsoleUser' | /usr/sbin/scutil | /usr/bin/awk '/Name / { print $3 }')
weblocPath="/Users/$currentUser/Desktop/Test Webloc.webloc"
/bin/cat << 'ENDOFWEBLOC' > "$weblocPath"
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>URL</key>
<string>https://community.jamf.com/t5/jamf-pro/can-t-create-composer-webloc-desktop-item/td-p/267841</string>
</dict>
</plist>
ENDOFWEBLOC
/usr/sbin/chown $currentUser "$weblocPath"
/bin/chmod 444 "$weblocPath"
exit 0
Instead of using a webloc, have you tried AppleScript? You can create an App, change the icon, and push the app to the dock. Users would click this and the website would open. The example attached opens portal.office.com to their default browser.

Instead of using a webloc, have you tried AppleScript? You can create an App, change the icon, and push the app to the dock. Users would click this and the website would open. The example attached opens portal.office.com to their default browser.

Thanks for your input. I had not tried this format for AppleScript, had found another article that had the script open safari to a specific URL, which doesn't work for us because I want the URL to open into the current default browser, whatever that might be. Your script might do this though, but then the problem is with the dock. We don't want to push URL shortcuts on user's docks, we customize them during setup but after that, they get very convoluted and pushing them after the facts would result in a mutiny. We want to push them to desktops, inline with our Windows systems. Composer did this so easily, and if it's no longer working because of the latest macOS versions, Jamf should really fix it. I've opened a support ticket, will see what happens.
@bootrec In 2020 you weren't running macOS Monterey, or probably even Big Sur. If you've still got a Catalina system available try your old process there, and if it works you'll know you're fighting a macOS change and perhaps it's time to look at using a script as a .webloc is simply a .plist file with a different extension, and all you'd need to do is write the contents of the plist. Here's an example script that writes a .webloc for this Jamf Nation thread:
#!/bin/sh
# Write Test Webloc.webloc to current user's Desktop folder
currentUser=$(/bin/echo 'show State:/Users/ConsoleUser' | /usr/sbin/scutil | /usr/bin/awk '/Name / { print $3 }')
weblocPath="/Users/$currentUser/Desktop/Test Webloc.webloc"
/bin/cat << 'ENDOFWEBLOC' > "$weblocPath"
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>URL</key>
<string>https://community.jamf.com/t5/jamf-pro/can-t-create-composer-webloc-desktop-item/td-p/267841</string>
</dict>
</plist>
ENDOFWEBLOC
/usr/sbin/chown $currentUser "$weblocPath"
/bin/chmod 444 "$weblocPath"
exit 0
works fine here with MacOS 12.5