The injector sits atop a seal. These seals appear to be some sort of rubber. Your seal has hardened and shrunk, allowing the injector to move on the seal. Definately not right. You might as well order up a set of new seals and replace all of them, since your spider is of an age where all rubber components start to harden and fail (rubber wise). The seals are not very expensive, but the problem is that the rubber hose connectors on top of the injectors will also be starting to harden and be difficult to get off the fuel rail. (also hard to get back on). You should do one of two things.
1. remove all the injectors complete with the fuel rail as an assembly. replace all the injector seals, and replace the injector/rail assembly. This will save you from having problems removing and replacing the injectors from the rail.
2. Remove all the injectors from the intake manifold and the rail and send them off to have them rebuilt complete with new top hoses (which attach the injector to the rail.
The rebuilt injectors will be returned to you with new bottom seals. Then reassemble the injector/rail assembly. Sprule Injection Service can do this rebuilding of the injectors for you. When I had mine done a couple of years ago, the whole thing cost a little under $200 if I am remembering correctly.
Be sure to keep everything clean and don't let any foreign objects fall into the injector holes while you are doing this work. While your injectors are out of the intake manifold, plug the injector holes with paper or cloth to keep everything clean while the injectors are out being rebuilt.
Robert