JSON-RPC Error when editing gas limit on custom network(s)

[ibrahimtaveras00]

Describe the bug

I get a JSON-RPC error when attempting to confirm a txn after having edited the gas limit
Happened to me when testing the two following networks:

Optimism Testnet = https://chainid.link/?network=optimism-kovan
Arbitrum Testnet = https://developer.offchainlabs.com/docs/public_testnet

Screenshots

Seen here = https://recordit.co/J7rQH8dlA2

To Reproduce

1. Ensure you have the Optimism Testnet on your wallet
2. Send a txn to another address, or tap on this request link:

https://metamask.app.link/send/0x2f318C334780961FB129D2a6c30D0763d9a5C970@69?value=5e16

3. When on Confirm view, edit fee > Gas Limit value
4. Attempt to Confirm

Expected behavior

I should be able to edit gas limit value without receiving an error upon confirming

Smartphone (please complete the following information):

• App Version [Optimism] Feature/custom network gas estimates #2865 and 2.6 release

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to be added after bug submission by internal support / PM
Severity

• How critical is the impact of this bug on a user?
• Add stats if available on % of customers impacted
• Is this visible to all users?
• Is this tech debt?

[omnat]

Did this happen only on Optimism and Arbitrum specifically or other custom networks like Polygon too?

[ibrahimtaveras00]

So far I only saw this happen on the testnets for Optimism and Arbitrum since the values were defaulted to decimals. I think any network that defaults to decimals for GWEI will also have this same issue.

[konigra]

Hello, I added a custom network (test network) and I have a custom token there, too.
On the Browser extention, I can send the custom token through the testnet without a problem. No gas fees needed.

On the mobile metamask although it is not working. Customizing and lowering the gas fees is not possible. I can confirm this is an issue also on custom networks

[github-actions]

This issue was closed because it has been stalled for 7 days with no activity. If you feel this was closed in error please reopen and provide evidence on the current production app. Thank you for your contributions.