Sun Scorch?

[King Carrot]

Sorry for the poor photo quality but I only have a point and shoot and it’s not very good at close ups. Can this be anything other than sun scorch caused by the tom being in too smaller cell during some hot weather? I transplanted similar sized ones into larger pots last week and was thinking of transplanting these straight into a greenhouse this week. All the other tomato varieties look fine and the only difference is that these are rather big for the root space they’re in. I’m always careful to avoid getting the leaves wet and these have been growing outside under plastic (well ventilated) during the day and brought inside at night. The variety is a Latah/Gardeners Delight type cherry, cross, now at the F5 stage.