Comment 54 for bug 1003309

Maybe a new(?) helpfull fact: After using the workaround, I did

update-initramfs -v -k all -u

and collected the sterr and stdout for analysis.
And, stderr tells exactly two lines (one for each of the two installed kernel versions):

cryptsetup: WARNING: invalid line in /etc/crypttab for lda -

'lda' is the name of the LVM volume group that resides on the encryptet partition!