As noted in my post A Brief Introduction to Numbers 21, these contradictions are the result of inserting a story from the Elohist tradition (Num 21:4b-9) here in P’s 40th year of the wilderness period.

This short story is thematically part of the Elohist “why did you bring us up from Egypt to die in the wilderness” tradition (see also Ex 14:11, 17:3; Num 11:1-6). It is misplaced here and contradicts its immediate context on two perceivable accounts:

While the people complain of no water (which is a reoccurring theme throughout this tradition), both the immediate context before (Num 20:9-12 from P) and after (Num 21:16-18 from J) present the Israelites with ample water. The “us” of this episode explicitly qualifies the Israelites as the Exodus generation, that is the 1st generation Israelites: “Why did you [Moses] bring us up from Egypt [= the generation that left Egypt] to die in the wilderness?” Yet where this story is now placed this is impossible. In Numbers 21 we are in the 40th year and all those whom Moses brought up from Egypt save Caleb and Joshua are now long gone (see also #238-240)—599,998 corpses strewn across the Sinai peninsula, or wait, 625,548 corpses depending on the tradition one follows (#116)! Before this text was placed in its present context, it must have originally been part of the Elohist stories of the 1st generation Israelites.

If, as scholars surmise, the compilation of the JE text preceded P’s redactional inserts, then we might speculate that an earlier version of just a JE narrative, that is a version without P’s texts, would not have posed these textual problems. It is only with the insertion of P’s account of the arrival at Kadesh and Aaron’s death that the we now find ourselves in the 40th year of the wilderness itinerary and thus too with the 2nd generation of Israelites. The JE text, therefore, might have originally proceeded from J’s Edom story to E’s “why did you bring us up from Egypt to die in the wilderness” story, and the narrative chronology of these events might have been envisioned as happening early.

Reference to “this putrid bread”—the manna—is also quite interesting here. It almost comes as a gloss. Interesting enough we have heard surprisingly little about the manna, which at least according to one tradition fed the Israelites for 40 years (e.g., Ex 16:35)! It is often referred to in the earlier parts of the wilderness tradition and thus might lend credence to the view that this episode was originally placed at an earlier point.

Also, the mention of “this putrid bread” here would seem to place this tradition in with those that claimed that the manna was the only food that the Israelites ate in the wilderness (e.g., Num 11:6). Now we all know this just wasn’t the case—at least according to contradictory traditions that spoke of the Israelites feasting on cattle, goat, sheep, and lamb-skewered shish kabobs! See #227. Was there only manna to eat OR not? (Ex 16:35; Num 11:6 vs Ex 12:38, 17:3, 24:5, 34:3; Lev 1-27; Num 7, 9:1-14, 28-29).