I think I found the underlying cause:
dblatex depends on texlive-math-extra which is a real package in jessie
and a virtual package in stretch, provided by texlive-science.
This gives apt a hard time to find the correct solution (install
texlive-science and remove texlive-math-extra), and failing to do so apt
decides to remove dblatex, triggering the bug.
Please switch the dependency from texlive-math-extra to texlive-science
(and also drop the superfluous mktexlsr calls) and upload to sid
immediately.
This should make apt find the correct solution and no longer decide to
remove dblatex. So you can skip fixing the package in jessie if the bug
is no longer triggered.
Further packages in stretch that depend on texlive-math-extra:
cadabra
lhs2tex
sisu-pdf
pycorrfit (Recommends)
science-typesetting (Suggests)
from piuparts jessie2stretch tests:
cadabra: gets removed while upgrading from jessie
lhs2tex: texlive-math-extra survives the distupgrade to stretch
sisu-pdf: gets removed
pycorrfit: (--install-recommends) texlive-math-extra gets removed,
but texlive-science does not get installed.
Andreas
