custom symbol insertion

[TNW]

Using 10.5 on windows I am having trouble with consistent custom window symbol insertion into walls. They generally pop in ok, but when I perform: convert to group/duplicate array/convert to symbol, the newly created window symbol will not always insert into walls. I have to go back to individual symbol insertion. I have tried 3d and 2d insertion and played with all the insertion parameters I could think of. If there is a better way to insert multiple identical window symbols, please inform me.