We use have+ object + infinitive to talk about asking or causing someone to do something. Please consider my these two sentences in that sense.
a. Mr. Smith has me fix the issue of poor networking.
b. Engineers have the workers repair the roads on site.
and, in continuous form
a1. Mr. Smith has me fixing the issue of poor networking.
b1. Engineers have the workers repairing the roads on site.
They seem grammatically correct but very odd to ears, especially a and b. Why is this the case and how can I use causative verbs more naturally?
Any tips will be appreciated.