Rough 2nd to 3rd shifts appearing specifically in afternoon traffic heat is a classic sign of fluid degradation or mechatronic pressure issues that worsens at operating temperature. That thermal pattern is important diagnostic information worth sharing with any specialist you visit.
We run cold storage too, similar temperature range. Haven't seen dimensional warping after about a year of use, but we do check the plastic grade specifically rated for cold environments before buying. Not all standard crates handle it the same way.