Definition of squad numbers for Guild Challenges.

I really have a beef here, Guys. A couple of challenges ago, my guild had to carry a non-exsistent team because they had left AFTER a Guild Challenge had been set. This evening my guild had been drawn against a guild that only had 22 members, HOWEVER come kick off time the opposition suddenly had 23 teams! I had changed my squad to allow for holidays, and all of a sudden, without warning of any kind my guild is under strength for a challenge we had prepared for. EXPLAIN PLEASE?
This is something Developers have said they will look at.
The GvG matches the two guilds and selects the number of participants as the number in the guild with the lowest total members.
Unfortunately this then locks the guild at that number.
If 25v25 nobody can leave, but when less, anybody can leave down to that number.
It's going to be a challenge to fix, as there is no simple solution that jumps out at me.