Failed sponge

[Jackamus]

I have just recently taken, in my mature years - I'm 82, cake and bread making with varying degrees of success.
I have made this sponge before with great success however this time it failed and did not rise as expected. You can see from the attached photo that it seems to be only the outside skin of the sponge that rose. The inside appears dense. The only change I made this time was that I cooked the sponge along with a second successful, different recipe, sponge - one on the top shelf successful and the failed one on the bottom shelf. I allowed an extra 4 mins cooking time for doing 2 sponges together.
Any suggestions for the failure on one sponge?

 

[retired baker]

It looks like a mismeasure mistake of an ingredient.
I would do it again and see..
Or stick with the recipe that worked.