Every time a transposer or item filter tries to suck up items from one inventory and push them out into another inventory or tube, it throws a NullPointerException and just deletes that item.
[17:50:39] [Server thread/ERROR] [teckle]: ****************OH SHIT TECKLE BROKE*******************
[17:50:39] [Server thread/ERROR] [teckle]: Caught NPE in tryPush!, com.elytradev.teckle.common.tile.TileTransposer@3d6dc165
[17:50:39] [Server thread/ERROR] [teckle]: Exception follows, java.lang.NullPointerException
[17:50:39] [Server thread/ERROR] [teckle]: Here's some useful debug info, NTile com.elytradev.teckle.common.tile.networktiles.NetworkTileTransposer@1e8fe863 node WorldNetworkNode{position=BlockPos{x=527, y=4, z=74}, capabilityFace=null} network WorldNetwork{nodeCount=6, travellerCount=0, worldID=0}
[17:50:39] [Server thread/ERROR] [teckle]: ****************OH SHIT TECKLE BROKE*******************
So items will be sucked up correctly from the inventory on the input side, but will never emerge from the output side.
Trying to remove IC2 caused the game to fail to load due to Teckle not being able to find critical ores, so I could not absolutely confirm that the problem was due to Teckle alone.