I have encountered the following issue while using Bitcoin Core 0.20.1
Initially I started bitcoind with txindex=0 in configuration file Later I changed this option to txindex=1 and restartted bitcoind with -reindex key
After complete reindexing I have the following issue getbalance shows 0 (which makes impossible to use sendtoaddress resulting "Insufficient funds" error message) getreceived by address shows correct amount of 0.604 BTC
Before reindexing everything worked perfect. Only txindex option was changed in bitcoin.conf and -reindex key added to command line parameters. No other changes were made. Reindex was completed, since getblockcount shows correct blockchain block count.
I am running Bitcoin Core v.0.20.1 on Debian 10 on Testnet3