raihaan I have also tested it with a new installtion of jenkins 2.266. I configured a job to mimic our configuration where I discovered that it breaks.
That is, using the "Conditional steps (multiple)" with an inner step of "Trigger/call builds on other projects" (from the Parameterized Trigger plugin).
This is the result after saving the config and reopening it:
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The UI below it is broken and no buttons are functional.
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The brwoser console log also contains some errors:
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Whether this is a problem of the Conditional Build Step plugin or the inner step (in this case the Paramterized Trigger plugin) I can not tell.
Using a different inner step works, as well as using the trigger step outside a conditional step.
AFAICT this is unaffected, I've tested it with the latest jenkins 2.266