barwidth in histograms is not the same

My data looks like this. If I plot a histogram of pH.Value for a specific Uniprot.Recommended.Name on a grid based on Space.Group with code like this

library(tidyverse)
ggplot(data = filter(massaged, Uniprot.Recommended.Name == "Myoglobin")) + geom_bar(mapping = aes(x = pH.Value)) + facet_grid(. ~ Space.Group)

I get a plot like this .

Why I have very thin bars (lines I would say) in the second Space.Group (P 21 21 21) and decent-width bars in the fourth Space.Group (P 43 21 2)? Can I have an equal bar width?

Thanks.

Ps. I did head -n 1001 data > dummy.tsv to my data. If you want the whole dataset just ask.