My application has been working fine from Visio 2003 to 2016 until a recent Visio update. Sometimes when I am checking to see if a cell exists using the CellExistsU function, the cell does exist but after calling this it vanishes. I have disabled updates and gone back to CTR 8431.2094 and the problem does not occur.
Anyone else seen this behaviour. For now I have disabled updates, but this is not really a satisfactory solution going forward.
Seems to have been introduced in Version 1709 (Build 8528.2139)
This now seems to have been resolved by Version 1711 (Build 8730.2127)