Powerpoint 2016 - master slide table text issue

[siuko]

We have a strange problem here that if you insert a table into a Master Slide and enter some text into it

 

When you next re-open the file and go to master slide view and try and edit the text in a table cell it automatically selects all the text contained in that cell (so typing as normal overwrites each letter with the next)

 

A text box in master slide view doesn't have this issue

 

And a table in normal view doesn't have this issue either

 

It is only tables in the master slide view

 

Anyone seen this before?