Is there an existing issue for this?

There's currently an bug in webui 1.5.0~1.5.1 that cause img2img batch to failed using with controlnet
for details see issue post #12149

The fix has already been merged to dev see PR #12164

If you are on 1.5.0~1.5.1 and need img2img batch to work now
in Settings > ContronNet > check Do not append detectmap to output

with controlnet useing the ablve option should suppress the issue
but if your experiencing this issue with other extensions that I suggest either switch to dev brunch or downgread to 1.4.0

Cause

some changes was done to batch img2img savem now that tries to save every image with gen info
the issue is that some extensions generating extra image that does not contain corresponding info (like control detectmap)
as such web UI fails to retrieve the info and triggers an error

Mikubill/sd-webui-controlnet#1848