The text of my signs is suddenly sideways:

I have signs placed on the front of a bunch of autocrafters, but the text seems to be facing at a 90 degree angle perpendicular to its sign. If I dig the sign and replace it the problem goes away, but only until I log out and back in again.
The problem only seems to affect signs that face east or west. Signs facing north or south are fine.
This initially happened after I installed the
Storage Drawers mod, but it wasn't corrected after disabling the mod, so I think that was just a coincidence. The problem also affects the "icon" on the front of the drawers from this mod.
It seems likely that it's something I did. Could Drawers have made a change that persisted even after disabling the mod?
This is happening on a personal single player server. I have the following mods installed and enabled:
- awards
- bonemeal
- boost_cart
- builtin_item
- caches
- caverealms
- cblocks
- coloredwood
- colormachine
- cutepie
- darkage
- datastorage
- digtron
- dmobs
- doc
- drawers
- ethereal
- homedecor_modpack
- hudbars
- infinite_chest
- item_drop
- large_hotbar
- mesecons
- minetest-3d_armor
- Minetest-WorldEdit
- minetest_doc_minetest_game-a9383c9
- minetest_hbarmor-bfc5f8c
- minetest_hbhunger-da70eba
- minetest_tsm_chests_dungeon-b1e4889
- mining_plus
- mobs_animal
- mobs_monster
- mobs_redo
- moreblocks
- MoreMesecons
- moreores
- mybricks
- mymeshnodes
- no_drowning
- pipeworks
- plasticbox
- signs_lib
- stained_glass
- technic
- throwing
- torches
- travelnet
- treasurer
- trmp_Pack
- unifiedbricks
- unifieddyes
- unified_inventory
- unified_inventory_plus
How do I troubleshoot this problem?