Object appears only on printout

Yan_Woellhaf Based on what you've described, the most logical explanation is the VBA code is using the Range.Copy method to transfer the data to the hidden sheets. For example:

Sub CopyPasteAll()
    Sheet1.Range("A1:C15").Copy Sheet2.Range("A1")
    Application.CutCopyMode = False
End Sub

When you copy/paste a range, it will include any shapes present in that range; furthermore, any subsequent copy/paste procedures will not overwrite shapes in the destination range (they will persist). At some point, a user inserted the blue arrow into their input sheet, then ran the VBA code, which transferred the arrows to the hidden sheets, and they've been there ever since.

Consider an alternative method for transferring the data. For example, use the Range.PasteSpecial method to paste values only:

Sub CopyPasteSpecial()
    Sheet1.Range("A1:C15").Copy
    Sheet2.Range("A1").PasteSpecial xlPasteValues
    Application.CutCopyMode = False
End Sub

A more efficient method, though, would be to copy the source range to an array, then output the values to the destination range:

Sub CopyToFromArray()
    Dim arr As Variant
    arr = Sheet1.Range("A1:C15").Value
    Sheet2.Range("A1").Resize(UBound(arr, 1), UBound(arr, 2)).Value = arr
End Sub

Without seeing your code, this is just my "best guess". Hopefully it applies to your situation and can be adapted to meet your needs. If not, then please disregard. Cheers!