Although the installer seems to recognize existing labels on Linux partitions, it seems that it does not look at labels of non-Linux partitions. So, having a Windows partition with label / causes strange situations (df and mount give wrong information) and having such a partition with another label may cause even more problems, I guess (the latter is untested). Note that this bug report is written with too little knowledge about the exact behaviour of the installer and mount c.s. w.r.t. labels, so some things might be a bit different.
How do you create a Windows partition with a label on it? My understanding is that labels are tied to the ext2 filesystem, so if a partition is formated for Windows I don't think it can have a label.
It originally was an ext2 partition with a Linux install, but before installation I changed the partition type to 0x0b for some tests I was doing with the installer to prove another bug. See also my e-mails about labels to the testers-list on August 1, 2000. Of course this is a very rare situation, but it can happen, for example when someone renames it partition to a Windows partition for a later Windows install, and the result is quite dramatically, I think, and someone need a detailed level of knowledge to understand what's going on.
Thanks for the feedback - I'll have to think about what bad things this could cause to happen...
We depend upon the partition type to be an accurate representation of what type of filesystem is on that partition.