Using Unguided Stages in Polynomial SQP Guidance causes "Index was outside the bounds of the array" error.

[DomKe1205]

MechJeb Version

Tried it on MechJeb2 – DEV 2.16.0.0-1704 and MechJeb2 – DEV 2.16.0.0-1705

KSP Version

KSP 1.12.5.3190

Description

When enabling and entering Unguided Stages in the PSG Settings window, Mech Jeb seems to fail and shows a Index was outside the bounds of the array in the Ascent Guidance window and in the console.

Replication Case

https://imgur.com/a/g7PUi1O

KSP.log

https://pastebin.com/mHcr4dUr