But your oven wasn't inactive was it? You were using it as a larder.
So your thread title is a big lie.
Why did you store milk in your oven? I cannot imagine a situation where there was nowhere else to put it. How long was it there?
Was 'hide the milk' one of those 'we went a bit bonkers over lockdown and couldn't find anything to do' games? Thank god it wasn't hide and seek or someone would be skeletonised in the back of the garage by now!!