Interstadial, interstitial, these are hard words
I found an alternate to Marcott, a suggested timeline based on a number of different sources, so Marcott is no longer the only one. Some of this is based largely off an older study so take it with the appropriate grains.
https://andymaypetrophysicist.com/cl...t-18000-years/
The point is, all these proxies are not great measurements and so we are left with huge uncertainty. The uncertainty/error bars are left off the cartoon version... and also, left off every media report about this, ever.