NOTE: hajimehoshi/ebiten/issues/2304 Ebitengine has now fixed the issue.
Reproduceable case of number of pow's arguments must be 1 but 2.
Ebitengine version has to be 2.4.0 or 2.4.1 to reproduce the issue (this repository uses 2.4.1). Older versions does not have this issue.
To run type go run github.com/cedriclikescode/ebitengineShaderPow@main in the terminal.