This brings up a great point- typically, engineers have limited exposure to technical writing. Personally, as an undergraduate, I was not required to take a technical writing course but it was integrated into many courses in the curriculum. However, even with the writing integration, writing required by industry, such as SOP’s, quality documentation, DSD’s, DHF’s, etc are not things that were integrated into the curriculum, even though many engineers will encounter these at some point in their careers.
Personally, I have come across SOP’s in my previous job that was incomprehensive. It become my job to update the SOP’s in question so that they were able to be better followed going forward. From my understanding, the previous person made them difficult to follow for job security reasons. They thought that by leaving gaps of knowledge in the SOP, it would ensure that they were the only person knowledgeable enough to operate the machine, thus securing their position at the company but all it really did was frustrate and confuse others.