drone steps are guaranteed to run sequentially, and will wait for the prior step to execute. It is therefore likely a configuration problem with your yaml file, however we need to see a complete working example that can be used to repeat the problem. Without a complete working example, it is really hard to debug.
It is also possible you are running an old version of drone, and are not taking advantage of the latest set of yaml improvements. Please also include your drone version number in reports.
This tutorial is from drone 0.5 and is not longer a valid configuration. Please do not use.
We tried with 0.8, but our pipeline is not triggered every time and we have not much time to troubleshoot further.
0.7 was an unstable release and should be considered end of life, without support. I recommend expediting your upgrade to 0.8 stable so that you can take advantage of the numberous improvements and 30+ bug fixes.