Mechanical interlocking joints have been used for thousands of years in carpentry and timber designs but have become less common due to the convenience and cost efficiency of glue and metal fasteners. Recently, these interlocking techniques have been re-examined to expand the capabilities of additive manufacturing. Additive manufacturing has gained popularity, in part, because of its ability to create geometrically intricate designs. However, most additive manufacturing processes are constrained by the size of a build plate and the bond strength between materials. Interlocking joints can be used to combine additively manufactured structures to extend past the dimensions of a build plate and reinforce the interface between multi-material components. Most of the current research surrounding the applications of interlocking mechanisms to additive manufacturing investigate interlocks that connect prismatic structural members. Yet, one of the most important aspects of additive manufacturing is its ability to fabricate complex structural designs. If topologically intricate structural members have an adverse impact on the efficacy of the interlocking mechanisms that connect them, then their behavior must be more carefully accounted for. Thus, it is important to understand how the topology of the surrounding structure impacts the mechanics of the interlocking joint. This work presents experimental results investigating how the mechanical properties of beams with an identical central Mortised Rabbeted Oblique (MRO) splice interlock are affected by different end topologies. The beams are optimized to minimize strain energy and are designed for different lengths and maximum allowable volume fractions. All optimized beams are compared to a standard prismatic beam for the same design space. The beams are experimentally tested under three-point bending. Results indicate that the end topology of the beam significantly impacts the failure mode of the specimen.