Devnet: "transaction reverted during simulation" false positive on every transaction (succeeds on submit) — same symptom as #208

[tork3n-zergfi]

Summary

Every transaction signed via Phantom on Solana devnet triggers the red
"This transaction reverted during simulation. Funds may be lost if submitted."
warning — but if the user signs anyway, the transaction lands on-chain and
executes successfully.

Looks like same symptom as #208

Environment

• Phantom version: 26.11.0
• Browser: Chrome Version 146.0.7680.164 (Official Build) (64-bit)
• Network: Solana devnet (Testnet Mode is enabled in Phantom Developer Settings)
• Dapp: localhost:3000 (custom dapp, but reproducible across multiple unrelated transactions)

Reproducible on 100% of devnet transactions for our app, regardless of
the instruction. First-time and repeat actions both fail simulation.

What we ruled out on our side

• ✅ Other wallets (Solflare, Backpack) on the same dapp do not show the
  warning and submit the same transactions cleanly
• ✅ Toggled Phantom Testnet Mode off/on, reconnected dapp, hard-refreshed
• ✅ Verified the dapp connection uses devnet (clusterApiUrl('devnet'))
• ✅ signTransaction flow only — the dapp does not use
  signAndSendTransaction; submission is via dapp's own RPC connection