Google's next flagship is slipping again, and this time the reason reportedly runs deeper than polish. According to multiple reports, Google DeepMind has delayed Gemini 3.5 Pro from a June target to around July 17 and thrown out the model's base — the foundation built on the Gemini 2.5 Pro architecture — to start a fresh pre-training run. Google has not officially announced a date, and a spokesperson declined to comment on the timeline.

What 'scrapped base model' means

Rather than incrementally refine the 2.5 Pro foundation, DeepMind reportedly abandoned it outright — pulling the architecture from production pipelines days before a targeted deployment and opting for a ground-up redesign. The trade is a near-term delay in exchange for what the reports describe as a "deeply upgraded foundation."

The reported reasons

Leaked internal evaluations, as characterized by the reports, showed the scrapped model struggling with recursive tool-calling, faltering on multi-step mathematical reasoning, and failing to hold structural consistency when generating complex, multi-layered layouts and SVG scenes — areas where rivals have grown more stable. The rebuild reportedly aims at a 2-million-token context window, a "Deep Think" reasoning layer for multi-step problems, and stronger image and front-end generation. Every one of these specifics remains unconfirmed by Google; treat them as leaks, not launch notes.

A brutal month for the bench

The delay compounds a rough June for DeepMind's roster. Noam Shazeer, a Gemini co-lead and co-author of the 2017 "Attention Is All You Need" paper, left for OpenAI; a day later, Nobel laureate and AlphaFold creator John Jumper departed for Anthropic, followed by researchers Jonas Adler and Alexander Pritzel. Demis Hassabis has pushed back on the narrative, telling Semafor DeepMind still has "by far the biggest and broadest research bench of any of the labs out there."

Alone in preview

The timing is unforgiving. With OpenAI's GPT-5.6 rolling out publicly on July 9 and SpaceXAI's Grok 4.5 already live, Gemini 3.5 Pro remains confined to a limited Vertex AI enterprise preview — making Google the only major frontier lab without a publicly available new flagship. Each day in preview after the GPT-5.6 launch compounds a positioning problem Google can't benchmark its way out of until the model actually ships.