[PyMOL] problem with alter chain Id

Hi,

I use a python script to copy an object, rotate it, alter its chain ID and then merge it with the original object.
Here is the relevant part of my script:

			angle = 360.0/monomers
			chains = ["A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z"]
			for i in range(1, monomers):
				currentChain = chains[i]
				cmd.create("%s_%s" %(solutionPymolString, currentChain), solutionPymolString, 1, 1)
				cmd.rotate([1, 0, 0], i * angle, "%s_%s" %(solutionPymolString, currentChain), 1, 0, None, [0, 0, 0])
				cmd.alter("%s_%s" %(solutionPymolString, currentChain), "chain='%s'" %currentChain)
				cmd.create("%s" %(solutionPymolString), "%s or %s_%s" %(solutionPymolString, solutionPymolString, currentChain), 1, 1)
				cmd.delete("%s_%s" %(solutionPymolString, currentChain))

This works fine with PyMOL 1.8.3 and 1.8.5 on my computer (macOS Sierra).

I have given the script to another person and for her it produces a very strange result.
The resulting structure is only visible in lines or sticks mode. And it looks like this in the sequence viewer:


She used the same input structure as I did but she has PyMOL 1.8.4 and uses Windows. Could this be a PyMOL bug?

Cheers,
Gregor