Vertical menu does not expand when showing Flexi pages

I have a left column menu. it is a default Joomla menu and right now I have some Flexi links and some joomla links as submenus of a parent link.
the menu is set to expand and display the submenus when clickingon the parent link.

However, when I click on a Joomla link (category blog style link) the indented submenus remain visible, but when I load a flexicontent page the menu collapses back into the top level list.

this is not acceptable both for this specific job nor in general as a behavior for the default Joomla menu.

is there an alternate menu I can use or is there something I can set to restore the menu behavior when loading flexicontent pages?

TIA

Actually, I had it the other way around. For some reason the items/articles that were not triggering the menu to expand where the ones I had left as regular joomla links.

By changing the type of link to a FC "Single Item" I was able to restore the menu behavior and it no longer collapses when displaying those items/articles.

This seems to happen only with single items/single article type links. I still have Joomla links to categories that are working fine with the menu, so far.

i will report any other behaviors related to this as I have searched the forum before in this regard but I found nothing. This way if someone in the future encounters the same issue they can refer to this post.