cUSD epoch transaction rewards not being indexed or exported to CSV in some cases

[aaronmboyd]

Epoch transactions sometimes not being indexed or exported to CSV

Environment

• Blockscout Version/branch/commit: Production site at https://explorer.celo.org

Steps to reproduce

As an elected validator, every month I export the epoch transactions from the CSV export page. I then import these manually into a portfolio tracker (Koinly). Koinly also reports the current balance of the addresses I import it to. I've noticed over time the "calculated" balance based on my imported epoch transactions diverges from the "reported" final balance in Koinly.

After investigation I found many epoch transaction payments in cUSD are not being indexed by Blockscout and reported for our validator address. There are over 20 missing transactions in the past year. Here's an example showing January 1st 2023 (epoch 1348), only the locked CELO rewards are indexed - the cUSD rewards are missing. The CSV export shows the same data.

Example link: https://explorer.celo.org/mainnet/address/0xfec62490e50b1038ab91ceedcb79e9e39269263b/epoch-transactions?items_count=300&reward_type=voter

Expected behaviour

All epoch transactions indexed by blockscout and reported in the CSV export.

Actual behaviour

Randomly missing epoch transactions with no clear association.