S'true. However, I've been able to circumvent this problem (in my 2400c) by partitioning the drive: the first partition on the 20GB drive I made slightly less than 4GB, and put the rest in a second partition. When I connect it to another machine in SCSI Disk Mode, only the 4GB partition shows up, and I can transfer data to and from it with no problems.
If you should try this, and both partitions happen to show up in SCSI Disk Mode, make sure to use ONLY the first partition; using the others will almost certainly corrupt them.