Some information

Operating system: Windows 10
Java version: openjdk 11.0.12 2021-07-20
Minecraft version: 1.12.2
Baritone version: 1.2.10-1.2.13
Other mods (if used): ClassicCombat-1.0.1.jar

How to reproduce

make two pillars
stand on one of them
take stone, and go to the other pillar with baritone making him bridge
take planks or any other block and try to bridge to the other pillar

Modified settings

blockPlacementPenalty 0
allowDiagonalAscend true
allowParkour true
allowParkourPlace true
buildInLayers true
mineScanDroppedItems false
legitMine true

Final checklist

• I know how to properly use check boxes
• [x ] I have included the version of Minecraft I'm running, baritone's version and forge mods (if used).
• [x ] I have included logs, exceptions and / or steps to reproduce the issue.
• [ x] I have not used any OwO's or UwU's in this issue.

do you know what the setting acceptableThrowawayItems does?

yes, but i dont quite know how to use it

#acceptableThrowawayItems <block1>,<block2>,<block3>,etc
example for a block would be minecraft:dirt
if you have more blocks you want to add to that list than the chat allows you can modify your settings file directly.
change or add if not already in there the line that starts with acceptableThrowawayItems after the space you add the blocks just like in the command, the blocks divided from each other by commas. so the hole line would look something like this:
acceptableThrowawayItems minecraft:dirt,minecraft:cobblestone,minecraft:netherrack,minecraft:stone,minecraft:oak_planks