I think they meant they have to rotate the 2x4 (or any rectangular that isn't square) grid by 90°.
I think Revit defaults to use the long side in the direction of the longest wall:

i tried "tab" before placing to no avail (and would need some preview of the grid before placing)
Make a feature request in ideas forum. It is a small annoyance, not the biggest. but i use point clouds for existing buildings and have to align and rotate anyway since not all ceilings are installed logically. For example, the architect made a decision on 2x4 light fixtures, then everything had to follow. And odd-shaped rooms get even weirder.
On the upside, all new ceilings typically are 2x2 or 4x4 and non-square tiles go away. This is due to LED fixtures that actually have better lighting in 2x2. Good riddance!
Revit Version: R2026.4
Hardware: i9 14900K, 64GB, Nvidia RTX 2000 Ada 16GB
Add-ins: ElumTools; Ripple-HVAC; ElectroBIM; Qbitec