SSE Game crashes on picking up arrow

[Andy40]

Hello

I've created a new arrow and projectile as part of a mod. There's a point in the game where the player enters an interior location and has to shoot the arrow into a wooden post, then collect it, adding it back into their inventory. For some reason, the game crashes as soon as the player tries to take the arrow. On restarting the game, the player begins at the cave entrance (last autosave) and can do the same thing again and it works ok. Any ideas why picking up the arrow would cause a crash first time round?

Thanks.