Sigma leaves TXs in pending state

[tonimateos]

https://drive.google.com/file/d/1BuXhkIHSI1097N5cpbMejLAQt1nrhmd-/view?usp=drive_link

Behaviour: about 1 in 4 TXs in Sigma are stalled in a "Pending" state that lasts forever. Example: https://sigma.explorer.laosnetwork.io/tx/0xc5413ac198de89581e820321c6de0458f6c583234badd26c93c17e1ea681dfcd

How to reproduce: try doing various TXs in Sigma yourself.
Alternatively:

• clone this repo: https://github.com/freeverseio/laos-smart-contracts
• go to branch tests
• go to folder batch-minter
• put whatever you want in truffle-config.js for the sigma network
• follow the README to do npm ci and set the .env file
• run ./node_modules/.bin/truffle exec scripts/test_coin_transfers.js --network sigma

It should do about 15 coin transfers. It never gets beyond the 5th or 6th. Sometimes 2 are enough to get stalled, sometimes 5...

ACCEPTANCE:

• I can run the script above many times and never have a pending TX issue

[tonimateos]

Possibly fixed by paritytech/polkadot-sdk#4639