A lot of projects are doing such fundraising. First rounds are covering basic development and as you said after a certain period of time they are going for real money. I saw enough projects that raised funds in ICO and then launched an IEO to collect more funds.
Such projects mostly are failed ones. IMO, we should not invest into those projects, no matter which sorts of fundraising they use, ICO, IEO, ITO, whatever.
I saw some projects run their ICOs at starts, months ago, then recent months/weeks came back to run their IEOs. Those ones should be avoided because you will highly lose money if invest in those projects.