2.4ghz is not bullet proof as many think or claim. While many manufacturers use 2.4 their frequency hopping operation differs from brand to brand. There can be some sort of field interference that Spektrum has difficulty coping with. Spektrum tends to dominate many flying sites so someone there may have a system wildly out of spec. Likewise tons of Chinese made 2.4 junk is common.
Technically 2.4 devices are not supposed to interfere with each other but with the plethora of 2.4 devices from garage door openers, security cameras to eBay RTF stuff there are bound to be many that slide under FCC's radar.
As a test try your system, or one that has experienced this issue, at another site or location. This will help isolate the equipment or location issues.