While you generate a brand new block, its corresponding block reward must mature first for 100 blocks till it’s spendable. In your case, it ought to present up as immature when you run getbalances (be aware the additional s).
$ bitcoin-cli -regtest -rpcwallet=minerwallet getbalances
> {
"mine": {
"trusted": 0.00000000,
"untrusted_pending": 0.00000000,
"immature": 50.00000000
},
...
This additionally explains why the stability of your “mywallet” exhibits as 89.99977500: After having acquired the block reward of 101 blocks, the primary block reward is mature (50 BTC). You then subtract the ten BTC you despatched to your different handle, and a small transaction price. After that, you generate one other block to the $MINER_ADDR, which makes the second block reward for “mywallet” mature, including one other 50 BTC to the pockets’s stability.
