Etabs Pull is causing Rhino to crash

#### Description:

When pulling bars with the Etabs adapter, rhino 7 & 8 crash. More testing to identify cause is needed.

#### Steps to reproduce:

#### Expected behaviour:

#### Test file(s):

Start by reproducing the crash while pulling bars through the ETABS adapter in Rhino 7 and Rhino 8, then narrow down which part of the pull operation triggers it. No source files, test files, or reproduction steps are named in the issue. Done means the bar pull no longer crashes Rhino in the affected versions and the cause is covered by an appropriate regression check.

Written by the indexing model from the issue text.