I just starting using kMyMoney and I have noticed an odd behaviour that it sometimes calculates the reconciliation balance incorrectly and then warns you not to finish reconciliation. However if you post reconciliation and immediately restart it without changing any cleared transactions It will calculate the correct figure to use and allows reconciliation to finish correctly without a warning.
This is after importing a bank statement with QIF and accepting the transactions matched with manually entered ones. KMyMoney Version 5.1.3 OSX-14.2.1 (23C71) homebrew installation largely from source on AppleSilicon.