zsh history bug ?

[Bernhard Tittelbach <xro@realraum.at>]

Hi,

for a long time now I've had a strange issue with zsh,
the source of which I haven't been able to track down.

It occurs on several of my computers and thus across several zsh
versions as well.
It probably has something to do with my zsh config, however very few
computers / users using it actually experience this problem.
It is very hard to reproduce the error as it happens only sporadically.
Were it not happing on several computers, I would put it down to memory
or hard disk errors.

This is what's happening:

# I type a command like the following:
% dtc -E  -I dts test.dts -O dtb -o test.dtb <enter>

# Then I get the last command from the history by using <arrow up>
# but strangley some chars seem to have moved and the CL looks like this
% dtc -E all -I ts  tst.dtss -O tb  -o est.dtbb<enter>

# again <arrow up>
% dtc -Wall -I ts tt.dtsss -O tb -o t.dtbbbb<enter>

# and again <arrow up> makes it even worse
% dtc -f -I dts tt.dtsss -O tb -o t.dtbbbb<enter>

# after entering another command, everything is fine again.

version: zsh 5.0.2 (x86_64-pc-linux-gnu)
config: https://www.tittelbach.at/zsh/.zshrc
	https://www.tittelbach.at/zsh/.zshrc.local
<arrow up> is bound to: up-line-or-history

any suggestions ?
cheers,
Bernhard