Hello Michael,
>>>>> Michael Eliachevitch <m.eliachevitch@posteo.de> writes:

    > Hello, I found a potential bug in org which I can reproduce with a
    > minimal configuration.

    > I added some org-capture templates purely for clocking into tasks
    > via the capture-menu. These capture templates are for things I
    > want to time-track but don't want to create a special entry for
    > (like eating and breaks), so I used the `plain' type with an empty
    > `""' template hoping it would clock into the given olp:

    > (setq org-capture-templates '(( "c" "clock into") ("cu"
    > "Unintended" plain (file+olp "~/org/clock_test.org" "Time sinks"
    > "Unintended") "" :clock-in t :clock-keep t :immediate-finish t)
    > ("ce" "Eating" plain (file+olp "~/org/clock_test.org" "Time sinks"
    > "Eating") "" :clock-in t :clock-keep t :immediate-finish t)))

    > My `clock_test.org' has the following headings:

    > * Time sinks ** Unintended ** Eating

This is amazing. I have run into exactly the same problem. I was
wondering whether to report it!

Oh, and I can reproduce the bug with your ECM.

Thanks for reporting it.

Best wishes,

Colin Baxter.