Two tone Tomatoes
What you are observing is not uncommon in tomatoes. If striping is to occur, it usually does so during the latter stages of ripening. You can still eat them though the parts of the tomato that are under the yellow areas may be harder in texture than the rest of the tomato.
Uneven ripening of tomato is sometimes called green shoulders or yellow shoulders because the stem end of the fruit ("shoulders"} stays green or ripens to yellow due to sunburn or other conditions. I’m not convinced that this is the case with your tomatoes since the yellow stripes run down most of your tomatoes. Uneven ripening is common in certain types of tomatoes though I don’t know how often it is observed in Jet Stars. Sometimes larger fruited tomatoes, such as Jet Stars, are more prone to this than smaller fruited varieties. I wonder if you have observed this in past seasons with your Jet Stars? Conditions that may promote uneven ripening include hot weather, poor canopy (foliage) development which leads to exposure of the fruit to intense sunlight, or poor/uneven soil moisture (too dry or too wet).
If you scroll down a bit at the following site, you will see what environmental factors might have caused this striping:
It has been reported that poor uptake of potassium by tomatoes can lead to yellow striping. This is further discussed at:
Related to potassium uptake, if you have not had the soil around your tomatoes tested within the last four years or so, consider doing this. Among other things, the test results will indicate the potassium level in the soil. Such testing can be done by the University of Minnesota. See: