I confirm this issue occurs, but in in private browsing only,
that is, whenever I click the arrow in the “all” cell in a normal tab,
then the collapsed state is remembered across all other opened normal tabs.
But if I open a private window now, then the previous collapsed state is not remembered.
And if I click the arrow now, then it’s remembered across all private tabs.
And, the collapsed state not being applied, is also for the arrow that’s over the separator for the ‘blacklisted hostnames’ cells to the bottom of the matrix.
Firefox 56.0.1 x64