I've been trying to narrow down this weird bug for the past couple days. It was working fine in v4.2.2 and the strange behavior started in v4.2.3. I've sort of narrowed it down to there being a grid column that is initially marked as hidden = true and then later shown using grid.columns.getAt(x).show().
Good - v4.2.2 Hidden
Good - v4.2.2 Shown
Bad - v4.2.3 Shown
A duplicate grid column header gets added and the alignment of the grid rows is not correct.
I added a simple test case. If you just do 'yarn install' and 'yarn serve' you should be able to get it up and running... I guess I can't upload a zip here. Here is a github repo: https://github.com/TMcKinley/grid-test
Here is where all the logic is at:
https://github.com/TMcKinley/grid-test/blob/master/src/App.vue
Thanks,
Tim