Walls go to Far....

[Eric Milberger]

This happens every now and again

When I extend a wall it will extend itself to the other side of the wall - no matter where I touch that wall.

[DGSketcher · Accepted solution]

You need to check your Building Material strengths. Priority based connections will apply and extend the wall at least as far as the reference line and sometimes further depending on strength values. 

[Eric Milberger · Accepted solution]

Thanks  - it was the strength.