fatal uncaught error 26.1.2

[Diggy]

I get the following error when trying to specify the MTU on an interface:

Fatal error: Uncaught TypeError: Cannot access offset of type string on string in /usr/local/www/interfaces.php:908 Stack trace: #0 {main} thrown in /usr/local/www/interfaces.php on line 908


Details that may be relevant:
* IPv4 set to static
* IPv6 set to DHCP
* Custom MAC set
* Device is a LAGG

If I don't try to specify the MTU, all settings are accepted.  As soon as I specify the MTU and click SAVE the aforementioned error occurs.

[Diggy]

Quick side question regarding MTU:

When configuring an interface, the help says "If you leave this field blank, the adapter's default MTU will be used."

If the adapter is a LAGG and I specified an MTU in the LAGG's config, is that MTU used?  In other words, what takes presidence with respect to an interface's blank MTU setting, the physical adapters' MTU, or the LAGG's MTU?