Hi, I can’t explain how the following happened. I was jumping a gate with a crane and an enemy flycatcher was jumping with me. I thought no problem, you have an interdiction nullifier fitted. The flycatcher deacloaks and burns to the gate. I decloak, align to a friendly structure, hit the nullifier and then warp. The bubble goes up and suddenly my ship slows down. I spam warp again and get the “You are within a warp disruption zone. Get 20000.0 meters from Warp Disrupt Probe to warp.” and “You are unable to align or warp to the selected object because your warp drive is unable to lock onto it.” notifications. With running nullifier.
Then I got scrammed and killed. What did I do wrong? Was the issue that the bubble went up after I hit the nullifier?
Can you post the killmail?
Burst Jammers disable your own Nullification effect. Check the description of the item.
Well I’m an idiot, thanks!
Nah, for just 270M, thats a valuable lesson learned. Two actually: first, Burst Jammers disable Nullification. Second, always checking the description of the items used on a ship. 
Ok so next time, don’t “decloak”, just hit the nullifier then warp. that’s not what caused your issue, but I know you don’t need to first decloak before hitting the nullifier
Two lessons for the price of one loss(mail), that’s indeed pretty generous. 
Up next: lesson how not to get scammed for the discounted price of only 100 mil ISK, from a reputable Jita trader near OP. 
It’s a common mistake you hopefully only make once!
Burst jams and higgs rigs disable nullification but many players don’t know that.
A fitting warning for this would be nice. We get them for less important problems in the fit.
The descriptions of the mods themselves usually staye such limitations
This module ceases to function when a Burst Jammer module or Higgs Anchor rig are fit.