gimp 2.9.x

[dinasset]

the error shown on the bottom line of the window is:
"none type object has no attribute e.width"

on the console where gimp 2.9 is launched there is a series of msg:
"..GEGL warning: blocking when trying to lock tile"

BUT, as said before, this happens after 2 full columns of tiles are properly processed (the blue is reduced)
what's wrong in the source?

thanks

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resulting layer