Couple of things to note:
On "Tell us more about this rental asset", Select that "No, I have not always used this item 100% for business.."
Then below that select the one for "I have used this item at least part of the time for business business, and also used it for personal purposes."
Date you started using it in this business will be 6/11/2018 (TWENTY EIGHTEEN). Percentage of time used in 2019 will be ONE HUNDRED PERCENT.
Now enter the correct prior depreciation amount of $4,459 and press on with life. The 2019 depreciation amount should be $8,397.
Keep miticulous notes on what you did and why you did it. This *WILL* come up again in the future and will most likely require a CPA. If you don't have notes, the CPA will be charging you out the arse to figure it out.