Usually, bad Gerrymanders take a few cycles to fall apart. This one is crumbling before the first ballot has even been cast.
D+8 is not a bad gerrymander. The Illinois Democrat party is just overly incompetent.
This was a district that gave a non-incumbent, aggressively moderate Republican a two-point win in D+6 form. Bumping it up to D+8 is not a good Gerrymander, it's a risky one.
And that was in the most pro-GOP cycle in over 100 years against a Democrat who probably couldnt beat Atilla the Hun. Even Seals would have won under the new lines.