My guess is that it isn't pushed all the way in. At least the Indivision AGA mk2 required considerable force. YMMV.
The IndiECS goes into a normal DIL-socket (Denise) while the AGA-versions use a PLCC-socket to be pushed onto the chip (Alice) something it was never designed for.
Mounting an ECS-Indi shouldn't require (much) more force than changing a Kickstart-ROM.
Corrosion in the socket, the socket not putting enough force onto the pins (it's about 25 years old), a broken/bent pin on the Indi or even something on the mobo might be the issue here (if it really is a HW-prob with the A2000 and not a SW-issue or a broken Indi).
