Contradiction with Exodus 25:9
Exodus 25:9 describes the tabernacle being built according to the specific pattern shown to Moses on the mountain, whereas Exodus 36:8 discusses the artists making the tabernacle differently without such explicit guidance mentioned.
Exodus 25:9: According to all that I shew thee, [after] the pattern of the tabernacle, and the pattern of all the instruments thereof, even so shall ye make [it].
Contradiction with Exodus 26:1
Exodus 26:1 provides detailed instructions for the curtains of the tabernacle, but Exodus 36:8 shows work being done without repeated reference to those precise instructions.
Exodus 26:1: Moreover thou shalt make the tabernacle [with] ten curtains [of] fine twined linen, and blue, and purple, and scarlet: [with] cherubims of cunning work shalt thou make them. [of cunning...: Heb. the work of a cunning workman, or, embroiderer]