Plots left truncated to 20k steps?

the lines in my plots seem to be left-truncated after around 20k steps. Is this intended behavior or a problem on the logging side. I use the built-in logging of huggingface trainer and the model resumed after around 20k steps. But the resume starts at the most recent global step, so no values should be overwritten. When trying to export the graph data as csv, the cells are completely empty for those missing values (so not a 0.0, NaN, null or something).