Gravity Arduino hield + 1602 Blue LCD display: Displays only first characters

I am teaching an IT subject to year 10 students and we bought gravity kits becuase they seem a great way to reduce the mental load of wiring correctly and that is motly going well.
WE are using the provided code for the temperature/humidity example from the zip file (Internmediate kit master).
Students (and myself) are pluggin in, checking connections for I2C, etc.
the display is often only showing
H 7
T 2
which seems to be the first characters of each display component, so it ALMOST works.
I have just re wired the project at my desk and have the same issue.
We did have this problem forone student and when we used the provided libraies and code (both Done again), it did display all text.

I had a quick search of the forum and dont see anything useful at this point.

Does anyone have an idea how to resolve this issue? clearly the display works (almost) , the sensor works and the code with libraries seems to work sometimes.

Any help much appreciated
David
Townsville, Australia.