vlookup table array

[Sallylou92000]

I have been using vlookup since 1995. Over the last few weeks I have not been getting the results I have expected and have discovered that copying the formula down, now changes the table array.
In the past I have always dragged or double clicked the formula down to the bottom of my selection, and the table array has remained the area originally selected. Now the table array moves down which results in the vlookup not looking at all of the correct data.
I know I am able to name the range which solves the problem, but for speed I prefer to just select the data whilst entering in the formula. (been doing it this way for 20 years)
I am using excel 2016, and I'm wondering if an update may have caused the change?
Any suggestions welcome...
thanks

 

[Chief Ace]

Did you lock your reference? Please look at sample attach.

 

[David Evans]

Are you certain that you didn't use Absolute Cell references, as opposed to Relative, in your previous work?

I've not seen any changes in Excel versions that would suggest there's been a change of approach via an update, and more to the point, I think this place would have been inundated with questions had that been the case.