Whats the issue?
When using Management reporter Microsoft states that manual journal entries should not be made directly to the retained earnings account. If manual entries are made then the company will experience translation issues and the Retained Earnings balance will be incorrect on the Balance Sheet.
How to fix it
1) Setup a new ledger account (ex.3902150 PY Retained Earnings) and this account will be used for manual adjusting entries. Please make sure to leave the Main account category blank (unless your MR reports are build using Main Account Categories and/or your role centers KPI’s are using the Retained Earnings account). 2) Process two entries A) A reversing entry to completely reverse the initial entry to retained earnings on the same exact date as the initial entry. B) A new entry using the Retained Earnings account created in the step above. 3) Update the row definitions in MR for the Balance Sheet by adding the additional Retained Earnings account created above (please make sure that the operators for your retained earnings accounts are properly reflected seen below). 
Hope this helps!