Replace All not working correctly for the last line

[danny]

TextPad 8.15.0 64 bit on Windows 10

Create a text file with 3 lines like this
A1
A2
A3

Do not add line break at the end of the third line

Go to menu Search > Replace
Find what: A3
Replace with: C3
Match whole words: uncheck
Match case: uncheck
Regular expression: uncheck
Scope: Active document

Click the Replace All button
TextPad shows Cannot find literal text A3

If we add a line break after the last line, then the Replace All works
If we change line 1 to A3, then the Replace All works for both line 1 and line 3
The Replace button and the Replace Next button are able to find and replace the last line, just the Replace All button is not